Wouldn't BUG be the coolest one to try? Gravewaker, Plaguecrafter and Frilled Mystic with Prime Speaker Vannifar.
I forgot about Gravewaker, it's a pretty cool card. So far, Hydroid Krasis as the top curve (with the potential to be a 4-drop and flip Climb) has been great for me. I'm not sure I'd like to put another 6+ drop. Krasis is the one card that won me games VS control, and the lifegain is incidentally good VS aggro. I don't think Gravewaker's applications are as wide, or at least as fast (it costs 6 to play and 5 to activate if I have a Familiar).
Plaguecrafter is probably not good in this aggro meta full of small creatures, Afterlife, tokens, etc...
Frilled Mystic is a card I consider for the SB but not in the main for now, because I mostly want to spend all my mana during my turns.
I built another Sultai deck with Vannifar, but I think this counters deck is something else. I don't want to sac my early drops to Vannifar, and the cards I can search for are not as impactful as a hard cast Krasis, at least in this shell.
There's surely a super nice deck to build with Reclamation, but I try not to play too many enchantments, they're usually terrible on an empty board and not very impactful VS control decks. Climb and Song are actually cards I try to get rid of, but I need more reps to see if something else can take the slot.
With 2 Biomancers out it cost 1BB to resurrect, and with a money landbase you potentially can do two activations each turn like bring back Plaguecrafter, and hold up for Frilled or whatever
I never had 2 Familiars on the board with something to do with it. Games usually end before that. But yes, Familiars stack and abilities become really cheap, that's one key of the deck : games with a Familiar are way easier to win.
and Mesmerizing Benthid which sort of works like your Sharktocrab but not against fliers, but isn't dependent on Familiar and is good with Climb as it's hexproof,
That's an intersting card to test, I'll have some reps with it. It looks like a good stabilization VS weenie decks and ok VS control. I hadn't noticed the tokens froze opponents's creatures. Trostani Discordant is in the same vein.
Whatever slots left in the deck that are open likely are filled with Incubation // Incongruity as its a creature heavy deck and this digs or acts as removal.
So, as much as I love pelt Collector, I currently cut them and play 4 Incubation // Incongruity instead. Collectors don't grow enough in this shell, and it's more important to find payoffs in order to make all those dorks valuable. Also, the removal spell is clutch in some MUs, without any it's really frustrating to lose to one creature.
Also, RDW and very fast aggros really force me to add lifegain in the maindeck, so I add 3 Knight of Autumn, which adds some tension in the manabase, but it's a necessary evil until I figure out something else. It also strongly pushes me towards Bant over Temur or Sultai.
Here's what I'll try :