Prismatic Omen and Doubling Cube can also help with your mana.
Last Stand could also be a fun thing to play.

Finest Hour and Rafiq of the Many allow for one shots with Progenitus

I already have a Doubling Cube in an artifact deck and don't like it as much as Prismatic Omen, which is one I'd forgotten about and would definitely include. Last Stand seems pretty situational but would be cool to play. As for Finest Hour and Rafiq of the Many, both of those seem awesome. I'd take Hour over Rafiq but either one or both would find a spot in here. Thanks a lot for the suggestions!

One thing i would add, Fist of Suns. Turns anything with annoyingly high costs to something affordable with a multi deck like this.

Thank you Shadov! Forgot about that one as well. Definitely adding to acquire board, thanks for the suggestion.

Sylvan Library gives you top-deck control and can draw you three cards in a pinch. Maelstrom Archangel lets you vomit something every turn, which can be a cheeky way to cheat something in uncountably. Maelstrom Nexus gives you cascade on your first spell, which is usually good.

Not a bad setup. I've got a few suggestions.

Here's a list of your targeted 1-for-1 removal, and they're overall quality.

• Maelstrom Pulse: 8/10. Nice choice.
• Utter End: 7/10. Costly, but effective.
• Terminate: 9/10. Solid.
• Pongify: 9/10. Solid.
• Kolaghan's Command: 9/10. Not the best removal spell, but almost always a 2-for-1 in fact, so very good choice.
• Crosis's Charm: 8/10. A decent catch all, though the mana might be clunky at times.
• Beast Within: 9/10. "Destroy target permanent" is pretty legit. The 3/3 means very little.
• Bant Charm: 9/10. Pretty solid.

While I think your choices of targeted removal are good, I think you'll find that cutting a few and going down to about 3 or 4 really damn good targeted removal spells instead of 8 to give yourself some room for more mass removal will be a huge improvement to your deck's ability to stabilize under more obscure scenarios.

Here's your current board wipes. Instead of 8 spot removal and 6 sweepers, it should be more like 8 sweepers and 3 or 4 spot removal.

• Supreme Verdict: 6/10. Good against creatures, except that they can still be regenerated, and they can dodge this with indestructible. It can't be countered, which is alright, and actually pretty good against mono blue decks in an attempt to keep Azami, Lady of Scrolls off the table.
• Terminus: 9/10. This answers all creatures, period. Excellent choice.
• Life's Finale: 4/10. Not the best sweeper, honestly. You never want to feed their graveyard, enabling their delve. All you're doing is playing a 6-mana Day of Judgment.
• Cyclonic Rift: 11/10. No comments necessary.
• Pernicious Deed: 7/10. Can be mana clunky, but can also be just the right card you need, destroying pesky permanents while leaving in play your higher-costed ones.
• Do or Die: 5/10. They get to keep the creature they want to keep. You're giving your opponent a choice. You're not sweeping the board because this only works against 1 target player. Good if your opponent swarms; literally just terrible against any voltron strategy.

What board wipes are you missing?

• Merciless Eviction: 10/10. Answers exactly what you need answered, and even exiles.
• Fracturing Gust: 8/10. Sometimes your opponent just has more mana rocks than you can keep up with, and cards like Caged Sun, Mirari's Wake, Mana Reflection, Omniscience, etc. It's an instant-speed catch all. Every deck plays artifacts and enchantments of some sort.
• Planar Cleansing: 8/10. You'll usually lose something from this, but it's a pretty good one regardless.
• Hallowed Burial: 9/10. Almost as good as Terminus, but that miracle cost is just insane.
• Final Judgment: 9/10. Another one that can defeat an indestructible Sigarda, Host of Herons.
• Perilous Vault: 6/10. Indeed answers everything, but better for decks that don't have access to white, which gives you all the sweepers. Since you have access to white, you don't need this one.
• Oblivion Stone: 8/10. Very good, but also predictable and seen from a mile away. Players will unlikely play into it.
• All Is Dust: 8/10. Costly, but gets around a lot of things and lets you keep your mana rocks. Keeping around your Chromatic Lantern can be pretty important. However, you're not playing too many colorless creatures (Steel Hellkite and Ulamog, the Infinite Gyre only), so you can't do a lot in terms of blowouts. This would be a nicer option if you had a Wurmcoil Engine and maybe a few more.
• Ugin, the Spirit Dragon: 9/10. This is just such a solid card. Can wipe out the board and then continue to keep the beats goin. The ultimate ability is pretty easy to get to and pretty much wins you the game.

What other spot removal is pretty good that you may have missed?

• Council's Judgment: 10/10. Answers literally everything that isn't a land. Voting isn't targeting. That can get through protection, through indestructible, through hexproof, through shroud, through literally anything, no matter how protected they think their nonland permanent is.
• Unexpectedly Absent: 9/10. There's plenty of shuffling involved in the format with fetch lands and tutors that you'll be able to turn this into a two-mana "Shuffle target nonland permanent into its owner's library." which is pretty damn savage.
• Detention Sphere: 8/10. Easily destroyed, but exiles a nonland permanent, which is pretty well answered. This is also easy to cast.
• Oblivion Ring: 8/10. Basically the same as Detention Sphere, except can't wipe out a slew of tokens or cloned creatures.
• Reality Shift: 9/10. One of the easiest to cast, and most effective removal spells for creatures I've ever seen.

One of the best ways to answer an opponent's commander is to literally just take control of it.

• Take Possession: 9/10. Split second and answers any permanent.
• Olivia Voldaren: 8/10. She's pretty good at taking over the mid-game, but will rarely follow through all the way until the end.
• Dack Fayden: 10/10. While it doesn't always answer the opponent's commander, the gaining control of an artifact is huge in the early game. Gain control of their Sol Ring if you weren't as fortunate to get one in your opener, putting you way back in the lead. +1 ability fuels your graveyard for cards with delve, and graveyard toolbox cards like Regrowth, Eternal Witness, Obzedat's Aid, and Profound Journey. Also, your Kolaghan's Command can Disentomb creatures.
• Puca's Mischief: 8/10. It's a "you may" ability, meaning you'd only do it if it's worth doing. Giving your opponent something like Urabrask the Hidden to get their Prophet of Kruphix is extremely worth it, for example. Especially with all of your removal.
• Debt of Loyalty: 9/10. If the creature regenerates, the rest of the ability resolves as well and you gain control of the creature indefinitely.
• Treachery: 9/10. I saw this in your aquireboard. Excellent choice.

Other suggestions.

• Expedition Map: 8/10. Probably better than Prismatic Omen because for 1, artifacts are easier to manipulate from the graveyard back to your hand, and is in that sense generally more recylcable. It gets any land, including Command Tower and Temple of the False God when you need it. It fixes your colors without exposing you to enchantment removal. It even synergizes with Trinket Mage.
• Gilded Lotus: 9/10. Probably better than Darksteel Ingot in general. It gets you solid colors and ramps really hard from 4 mana on turn 4 to 9 potential mana on turn 6. Synergizes well with cards that untap artifacts, like Tezzeret the Seeker and Ral Zarek. Also enables you to more easily cast Divinity of Pride.
• Urban Evolution: 8/10. Draw cards and ramp. Pretty solid.
• Reap and Sow: 8/10. Costs a pretty big amount of mana, but tutors a land into play untapped while destroying an opponent's land (perhaps a pesky Cabal Coffers, Gavony Township, or Gaea's Cradle).
• Mirari's Wake: 9/10. Much better than Heartbeat of Spring. Heartbeat is purely a card for a group hug deck, and shouldn't be played otherwise unless you really don't care at all that you're shooting yourself in the foot. Mirari's Wake gives you that effect alone at the competitive cost of just 5 mana, as well as pumps your creatures a little bit. Mana Reflection can make a Gilded Lotus tap for 6 mana and a Sol Ring tap for 4 mana, but it also costs more real life money as well as more mana to cast and doesn't pump your creatures.
• Clever Impersonator: 9/10. Always becomes the most powerful permanent in play. This is an extremely powerful card.
• Tooth and Nail: 15/10. If you want to lose friends, this is the most powerful card in EDH.
• Extra turn spells in general. Some I can suggest are Time Warp, Beacon of Tomorrows, Temporal Mastery, and Time Stretch. Temporal Trespass is a trap. That card isn't very good. Extra turn spells admittedly make more sense when you're playing Regrowth effects, however. Also, it's totally acceptable that you might be against taking extra turns, as I know some people don't like that.
• Mystical Tutor: 10/10. Set up those miracles like Terminus, and maybe throw in an Entreat the Angels or Bonfire of the Damned. Also just gets whatever you might need at the time, and at just 1 blue mana and instant speed, it's the best damn $6 you'll ever spend.
• Demonic Tutor: 10/10. Obviously a good card, but I can understand if you're opposed because it's a bit too good of a tutor. I'll personally play Mystical Tutor because I like miracles, but I hate hearing the groan in my playgroup's voices when I cast Demonic Tutor, so I just don't anymore.
• Birthing Pod: 8/10. Get to your big fatties more consistently. Gain control of your opponent's creatures and sacrifice them to this. Anything that gets you to Prophet of Kruphix more consistently is going to feel like a strong card.

Other cards not previously mentioned in your deck that I feel are lacking.

• Mind Spring: Good cost, but sorcery. I see Sphinx's Revelation in your aquireboard and hope that's replacing this eventually. Cards like Dragonlord's Prerogative at instant speed are going to feel better in general until you can get your hands on a Blue Sun's Zenith or Sphinx's Revelation.
• Sphinx of the Steel Wind: Powerful creature I guess, but I feel like there are bigger bomb drops for that kind of mana cost. Avacyn, Angel of Hope and Vorinclex come to mind immediately. Even an Avenger of Zendikar seems just better in general, especially if you were also playing Birthing Pod and Craterhoof Behemoth.
• Ulamog, the Infinite Gyre: Powerful card. If your opponents are playing Bribery, he's probably the choice. Instead however, if he wasn't a possible choice, the card your opponent would get would probably be worse than your commander: Progenitus, which is always a creature you have access to that they do not. Ulamog is at least better than Blightsteel Colossus, which exposes you to Acquire as well. Kudos for steering clear of Blightsteel.
• Shard Convergence: Good fixing, but poor in terms of mana ramp. Look at Skyshroud Claim. It can get two forest cards, which includes forest shocklands like Temple Garden, Breeding Pool, Overgrown Tomb, and Stomping Ground and can put them onto the battlefield untapped. As an easier-to-find alternative that you might have in your bulk collection, Ranger's Path does the same thing but puts the lands into play tapped. Ramping is super important, as you certainly know.

You have a lot more creatures than I would personally run in a 5-color deck. When I think of a 5-color deck, I imagine a creature base of just exactly what is necessary. Some ramp, some utility, and only the absolute highest-performance beatsticks. Narset, Enlightened Master is an example of a great one, but not for you because 27% of your deck is creatures. Eternal Witness is a fantastic card; my favorite card in fact. If I were to list the best creatures in your deck in order, here's probably the top 6.

1. Prophet of Kruphix
2. Consecrated Sphinx
3. Oracle of Mul Daya
4. Steel Hellkite
5. Keranos, God of Storms
6. Archangel of Thune

Here's what I think the bottom 5 probably look like.

1. Qasali Pridemage: artifact/enchantment removal doesn't need to be on an exalted creature. You're not even playing Green Sun's Zenith or Chord of Calling to make it more accessible, in which case Reclamation Sage is more reliable anyway because the Pridemage can have its activated ability turned off, and split second can blow it out. A good card in aggro; a meteocre card in 5-color.
2. Kira, Great Glass-Spinner: It's honestly not that difficult to work around, largely irrelevant on turn 3, sweepers are more commonplace than targeted removal in this format anyway etc. This could be Clever Impersonator, or if you're feeling hateful against a particular commander, Evil Twin.
3. Spiritmonger: It's okay. The best thing he can do is regenerate over your board wipes. He offers otherwise very little synergy, and feels underwhelming as a 5-drop when compared to other possible noncreature 5-drops.
4. Restoration Angel: There are very few ETB effects to even abuse here, which include an entirety of Trinket Mage, Dragonlord Silumgar, and sometimes Phyrexian Metamorph. Yeah, it can save a creature I suppose. It's above curve in general, being a 3/4 flash flying for only 4 mana, but could be something more threatening, and could be better if you were playing more powerful ETB effects like Woodfall Primus, Acidic Slime, Terastodon, Prime Speaker Zegana, Zealous Conscripts, Eternal Witness, or Rune-Scarred Demon. Again, restoration angel makes a card like Reclamation Sage look better than Qasali Pridemage for this deck.
5. Sphinx of the Steel Wind: Not too bad for a single creature, but I feel like there are more effective and threatening 8-drops in the format. Even Godsire seems better honestly, and he's not even that good here. If you were playing a card like Open the Vaults, then this card is a little better and makes more sense because you could reanimate it along with Thassa, God of the Sea, Keranos, God of Storms, Steel Hellkite, Chromanticore, and Phyrexian Metamorph.

You're well on your way to a nice EDH deck here. I hope I've helped inch you a little closer, and good luck! :)

-Logician - wow! I never expected such a detailed and helpful description and review; you really outdid yourself and for that I have to say thanks a lot and kudos to you. I don't have much time to play or collect anymore so I am obviously still working on the deck, but what you said was very helpful and I will do my best to edit soon with your tips in mind. I agree quite a few cards are in dire need of an upgrade or just downright need to be replaced.

I actually do own a few cards you suggested as well, like Merciless Eviction, Clever Impersonator, Skyshroud Claim, Eternal Witness, Avacyn, Angel of Hope, Gilded Lotus, Expedition Map, etc, albeit mostly in other decks (which I've been considering dismantling anyway). Quite a few - the tutors and mana ramp cards especially Demonic Tutor, Mystical Tutor, Mirari's Wake - I have been trying to get for a long time, and may break down and just order them from somewhere rather than try to trade as I prefer to do. As for the extra turns, I'm not opposed but I know my typical playgroup would despise my existence were I to use cards that enabled them, me already being the "annoying blue player" most of the time.

Anyway, thanks again for all your tips and analyses - I'm really impressed - and I can't wait to edit and improve the deck!