Reylt, the Contemporary Duelist1WUB
Legendary Creature - Human Warrior (M)
Reylt enters the battlefield with 2 -1/-1 counters.
Whenever you draw card, you may move all counters from one target permanent to another target permanent that shares a type with it.
Telvera, of The Cesspool1GB
Legendary Creature - Elf Shaman (M) G, Sacrifice another two creatures: Search your library for a creature card with converted mana cost less than or equal to the sacrificed creatures combined converted mana cost, put it onto the battlefield, then shuffle your library.
Noquarian, The Great Fissure4GUB
Legendary Creature - Leviathan (M) Eminence — As long as Noquarian, The Great Fissure is in the command zone or on the battlefield, Krakens, Leviathas, Octopus', and Serpents you control have hexproof until they attack. (they don't regain hexproof)
Whenever a Kraken, Leviathan, Octopus, or Serpent you control attacks, you may tap target creature or destroy target tapped creature.
It feels wrong that the counter manipulating commander isn't green. It's possible that it's fine either way but it feels wrong.
While requiring two sacrifices might seem significant it's rather irrelevant. This absolutely needs to tap or its game over once it hits the field.
Noquarian has a very strange ability. While the rules handle the ability just fine I wonder what your intent was for some scenarios. If you cast Noquearian do you expect creatures that had lost hexproof to regain hexproof. If it makes its way to your hand or deck do you expect the ability to 'reset'? What about when it's on the field and it does going to the command zone? With the way the rules work every time it changes zones it would 'reset', this granting hexproof. That aside it's a headache keeping track of what does and doesn't have hexproof. Also your creatures losing hexproof while this is on the stack is hilarious for everyone except the person casting them.
Telvera is crazy busted; she needs a T in that cost. That ability is also GU or mono-G, as per Neoform, Birthing Pod, or Eldritch Evolution, rather than BG. Green alone is perfectly willing to sacrifice things for value.
The other two seem fine, and I'll add that I don't think Reylt necessarily needs green since he's not actually adding counters to anything. Even just UB would be fine.
I think reylt not being green is fine, as it doesn't "add" counters per-say it moves them. Removing all counters at once feels black, especially with the -1/-1 counters it starts with. Also white for doublestrike.
I'm going to reimagine Telvera.
The Timing Gap in Noquarian is odd and is a feels bad for a mroe casual commander. Maybe if I switch it to be it static in play ability and make it "tap or destroy tapped" ability Eminence? And yes the flavor wizards usually goes with doesn't include whales, but could be a fun adjustment.
I really like the Leviathan; only I do think it would be better if "As long as they're untapped, those creatures have hexproof" or something a little more simple. Sure, it would be stronger, but I think it is less complicated and also boosts the tribe quite a bit.
Side note, I would be SUPER into a Sultai Leviathans & Friends commander deck.
Reylt would lead to some pretty degenerate Superfriends decks where you cast something like Ob Nixilis Reignited, use the +1, and use the card draw to send its counters to another walker so it can instantly Ult. While it's a far cry from Doubling Season (which you wouldn't be able to use in the same deck), no other legendary creature ramps up loyalty counters to such a dangerous degree.
Telvara, meanwhile, would lead to some decks that are pretty miserable to play against. I imagine sacrificing two guys to get a Woodland Bellower (Grabbing Eternal Witness) before sacrificing it and the guy it creates to grab a Phyrexian Delver to revive the Woodland Bellower (Grabbing Caller of the Claw and making 4 free tokens) before sacrificing the Delver and what the bellower grabs to get a Protean Hulk before sacrificing the hulk (Grabbing Surrak, the Hunt Caller and Sylvan Safekeeper) to fetch out an Eldrazi Titan that benefits from Haste (courtesy of Surrak) and possible Shroud (courtesy of the safekeeper). While this sort of chain may be balanced in "75%" or cEDH, this card would be degenerate at most play tables.