Hi, welcome to my deck tech. I will be doing a breakdown on my deck. DISCLAIMER: "I watched and read many other people deck tech before I eventually came up with this so it may not be that original."
You can only include 100cards in this format, I picked the ones that are more relevant to my synergy. I shall skip the explanation of lands, kill/removal spells, mana ramp, and certain cards in this deck as it pretty much straightforward.
Don't expect to win with Commander Damage because Atogs is a very weak tribe but with that say, that does not mean that you can't win with this deck. It's those unpredictable and sudden wins that makes this more fun.
1st Win Con (Winning with Lands): Yup, you are reading this right, winning with 10 gate lands. This is nothing new but since Atogatog is 5 colours and with the new set Guilds of Ravnica being released, lets bring this method of winning back. Either you could be really lucky and draw those gate lands and play them or you could tutor them with Maze's End or Circuitous Route. Gateway Plaza is the new 11th gate land being released in the new set and that just makes this method a little sweeter with more choices to pick from.
2nd Win Con (Winning with a Second Sun): After you played Approach of the Second Sun once, pretty much just try to play it the second time and you win. That simple and straightforward. You can speed up the process to draw it a second time as I have chucked in tons of draw spells.
3rd Win Con (Winning with Barren Glory): In my opinion, this is quite tricky because there quite a bit of thinking and combination to pull off. If you make a mistake it's pretty much game over to build back the board state. If possible, use the tutor spells to tutor for Barren Glory + Obliterate + Ugin's Nexus. U might also need to have Atogatog and either Psychatog or Thaumatog or Phantatog already out on the board depending on your board state. Play Ugin's Nexus + Barren Glory and if both get resolved successfully, start sacrificing all enchantments in play except Barren Glory to Thaumatog or Phantatog. Next, if Obliterate is not the only card you have in hand, discard all cards except Obliterate to Psychatog. Sacrifice all your Atogs to Atogatog and because Atogatog ability can sacrifice any atog which includes himself, sacrifice him to himself or alternatively, do not sacrifice any Atogs but do the next step. Finally, play Obliterate, to wipe everything on the board but because Obliterate can't destroy enchantment, Barren Glory will be the only card left on your board. Since Ugin's Nexus got destroyed, you take an extra turn after this. Just end your turn and you win during the extra turn. Obliterate cannot be countered thus, making this combination very sweet but make sure you really have all those cards in play else it's game over if you do it wrong.
4th (Insurance Policy): Since we are not playing many creatures and Atogs is generally a weak tribe, you do not want to be the target on the board, Ghostly Prison will make your opponent considered twice before attacking you. Alternatively, Door to Nothingness will have help you to remove any annoying opponent that keeps picking on you. I know playing Door to Nothingness to make someone lose is a cowardly method but seriously, if you look at this perspective, most of the time you will be doing pretty much small plays every turn as Atogs can't do much and their buff only last until end of the turn which sucks. Therefore, I usually wait off and try to pull off any of the 3 Win Con mentioned above.
5th (Just do it if you can): If you decided that you want to swing with commander damage or attack your opponents with your creatures, sacrificing Rancor or Spreading Algae to your Atogs repetitively to buff them if u have the mana to spare. You can also sacrifice Ichor Wellspring + Hatching Plans + the 3 Implement artifacts to your Atogs to buff them and draw cards. If you have mana to spare, the 5 spellbomb artifacts I included give you card draw as well when you sacrifice them to your Atogs. You can either attack with those big boy Atogs or just sacrifice them to your Commander and swing for commander damage. Chariot of Victory + Glaive of the Guildpact just make your commander stronger.
As much as possible, I will only start sacrificing Ichor Wellspring + Hatching Plans + the 3 Implement artifacts or 5 spellbomb artifacts for card draw only after I played Approach of the Second Sun once. This will guarantee you to draw it a second time 7th from the top of your deck and played it again to win the game.
All suggestion is welcome. How you build your deck depends on how much you are willing to spend and the type of synergy you are going for. I am going for a very budget build here so I try to get affordable range cards. If you have the cash to spare, replace By Force with Vandalblast. You could also include better removal spells as well. As mentioned before, I am not really going for commander damage with this build thus there is not much spells or equipment to protect the commander. I am building this with a fun and unpredictable winning methods. Thanks for taking your time out to read this. Have a Great Week ahead and Happy playing mtg.
Check out my other deck techs in my profile, I run: - Olivia Voldaren EDH - Reaper King EDH - Athreos, God of Passage EDH - Grimgrin, Corpse-Born EDH.