Elite Scaleguard is a great find. Maybe you could try Hardened Scales? Works wonders in my Hydra deck. Triggers each time you bolster. Fun deck idea.

In this particular deck I don't think you have enough creatures that enter the battlefield strong enough to evolve Renegade Krasis. And if they are, he will only evolve once.

Thanks for the suggestions! Not sure how I missed Hardened Scales. I was even thinking about how nice Doubling Season would be.

I was thinking the same thing about Renegade Krasis. I added Carnage Wurm, Outland Colossus, Vorapede (which may be problematic requiring 3 green), and Gravetiller Wurm.

Doubling Season was indeed my first choice as well. But at the time it came out I didn't need it anymore, except for overkill. Be aware that Hardened Scales doesn't double like Doubling Season. Every trigger that puts counters on it adds one more. So multiple trigger work better. Maybe adding Bioshift or Fate Transfer could be an unexpected combat trick or when your creatures get destroyed. Or in the case of Fate Transfer move counters from your enemies creatures to yours :).

I like both those, though I put them on my maybeboard since I already really need to reduce the number of cards. Maybe I'll end up putting Fate Transfer on my sideboard and I can swap it in if I know an opponent has the potential to have counters. Nice finds!

Inexorable Tide may be nice here.

Warden of the First Tree is a pretty good green 1 drop

Only if you decide to keep the splash of white though

Kaos_Kitty: I had Inexorable Tide in there initially, but it felt unnecessary and that by the time I was playing it there were already a ton of counters out. As a friend put it, it seemed to be a "win more" card.

Caz420: I tried splashing white at first, but it definitely seemed to run more smoothly just keeping it UG. Otherwise I might add it.

Add Kalonian Hydra for sure. I would do a playset.

AiryNeon, I definitely would if a playset wasn't one and a half times the current price of the whole deck.

you should try Protean Hydra it could be a nice and usefull to move all those counter with Bioshift

zyk, that's definitely an interesting idea. What would you remove to make room for Protean Hydra and Bioshift?

should try switch out Endless One for the Protean Hydra, a bit more mana expensive but you got that effect without loosing the fact that its evolve with the mana you can feed them.

and Bred for the Hunt switched for Bioshift, because as Bioshift is instant you can save any of your card by swapping counter on it. in fact you can also lead an assault with all you card ( your oponent should be blocking your massive stacked hydra whit a 1/1 token ) and switch all your +1/+1 to a creature that is going trough ( or your Avatar of the Resolute as he got trample) for a "ez" finishing blow. in fact you can still try to get more card with Tezzeret's Gambit (if not enought -1x Pongify +1x Tezzeret's Gambit )

And i forgot something, that hydra Bioshift combo work well with Managorger Hydra if you want to change your playstile sometime you can try it, but i think Protean Hydra will work better.

I'd recommend Lorescale Coatl and Forced Adaptation.

Both are cheap cards that offer dependable growth. Also the Coatl would combo beautifully with Bred for the Hunt.

slaftergames, I've toyed with the idea of Forced Adaptation or Ring of Kalonia, but I have a feeling it would slow the deck down. However, I haven't actually tested either of them.

Lorescale Coatl would be fantastic, especially with Bred for the Hunt and Tezzeret's Gambit. I'm really struggling to decide out what to remove, though. I also want to add Managorger Hydra, too. Thoughts?

That's a really tough one. My first instinct is to cut some Endless Ones, but I also just don't like Eldrazi so that's more personal bias than anything else. Honestly I might sideboard Pongify; you know the decks you'll be playing against better than I do, but it seems to me that unless a deck has a creature which specifically hobbles your strategy (like an Archangel of Tithes, an Azorius Guildmage, or some such thing), your massive counter-gorged creatures will probably batter the enemy's lineup enough that removal becomes redundant. I also wonder if the same could be said of the Champion of Lambholt, though I'm partial to that card in general; making your creatures unblockable may be unnecessary against some decks because the beatdown you'll be dealing will be sufficient anyway. I think that with the draw speed of this deck you can probably rely less on unblockable creatures and more on just overwhelming the enemy with size and numbers most of the time. I'd perhaps cut an Avatar of the Resolute as well; it's a great card but I think it's probably best saved until after the Fangren Firstborn and proliferate have begun their work, making three copies slightly more than necessary in my opinion. I'd also add at least a third Bred for the Hunt if you're going to add the Lorescale Coatl, since without that card draw the Coatl won't be any faster than Forced Adaptation or Ring of Kalonia.

All that said, it's an extremely tough choice; I like the deck a lot and you've definitely reached the point in the process where deciding what to cut gets really difficult.

Much thanks for the detailed response. I always appreciate an in-depth answer (not that short answers are necessarily bad).

I've had similar thoughts, actually. I must admit that Endless One is a little bit of an oddball here. To this point, I really like it in there because of its flexibility. It's super nice to be able to cast it as whatever would be useful at the time, whether it be with a single counter for one mana or a 4/4 to trigger evolve. Plus, it gets a free counter if Hardened Scales is already out. I cut one Avatar of the Resolute, one Champion of Lambholt, and sideboarded Pongify for the reasons you mentioned. Then I threw in an additional Bred for the Hunt and a set of Lorescale Coatls. After a bit of playtesting, I have mixed feelings about it. Sometimes it feels solid, other times it just feels "meh," so I'll keep playing around with it. We'll see what happens, especially because I'd like to get Managorger Hydra in there, too. Thanks again!

AVATAR. OF. THE. RESOLUTE.

Tried it. Was just kinda meh. See "Cards I've Tested."

Have you considered Curse of Predation? It seems to fulfill a similar function to Fangren Firstborn. It costs only 3 and survives creature removals, but as a slight drawback doesn't provide one additional attacking creature.

I wanted to, but it's not modern legal.

Eww I didn't take that basic thing into account! Embarassing! sorry for the stupid suggestion then : P

I'll try again with another suggestion. When you have Hardened Scales and lots of 1-drop creatures (Cloudfin Raptor, Experiment One, Llanowar Elves) I think it becomes ok to include some rings (Ring of Evos Isle primarily, maybe Ring of Kalonia). The consistent addition of 1 single +1/+1 counter at a time amplifies the effect from Hardened Scales to the maximum, and the casting cost of 2 with the very cheap equip cost of 1 make them usable relatively early in the game; additionally, the Evos Isle ring provides some (weak) form of evasion from single target creature removals, that is never a bad thing if you want to be aggressive.

As for what to replace with some rings, my suggestions are: definitely one of the Solidarity of Heroes (wonderful card but in a late game; no need for 3), then maybe some Strangleroot Geists (again, wonderful cards but in a deck that ends up accumulating lots and lots of +1/+1 counters on them without ever removing those counters, they end up losing what makes them special - the fatty undying)

Also I feel like experiment one should get priority over said Geists and be in 4x. As the game progresses and +1/+1counters start pouring down, the geists just lose undying while the Experiment one gets some quasi-free regeneration ability (this means it can 1)block fatties, 2)resist to deathtouch and some weaker board wipes like Day of Judgment (though not to the popularWrath of God and Damnation))