Unlike other blink effects, Thassa targets a creature you control, and returns it under your control. That lets you blink stolen creatures, and turns temporary steal effects permanent. That matters with Vedalken Shackles and Sower of Temptation. That's probably interesting enough to test it.
It can also be a turn 4 kill if you have a turn 1 creature, turn 2 Ballista, turn 3 Heliod, and on turn 4 you give both creatures lifelink and chump attack with the 1 drop. Still a bit of a best case scenario.
I don't have enough big artifact bombs to support Tinker currently, and Puresteel Angel is definitely a bomb. I also happen to run 8 colored artifacts for it to hit. It may end up being too strong, but it's hard to resist trying.
Unicycle is more interesting than Lightning Greaves, and has enough board impact to see a lot more play in aggro. I expect the common play pattern to be crewing it with an existing creature the turn it's played, and then either crewing with a new creature or equipping on a new creature on subsequent turns, so that it gets much more value.
Growth Charm is playable combat trick and a much better Regrowth, which are both things I'm happy to see.
Generated Horizons is a simple, slow ramp engine. It might not last since it takes a while to pay off.
Vazal, the Compleat is a very fun-looking green fatty. The body is fine by itself, and I don't know what shenanigans it's going to enable.
I'd probably SPLASH this card with just a few green sources in a deck that has library in it.
This is a great point. Once Upon A Time is castable without green sources in your opening hand. You can even run it without green sources if you really want a particular turn 1-2 play.
This isn't bad, but the difference between "draw one" and "draw two" is massive. I don't think this replaces Mulldrifter, but it could still find a home.
This is an easy swap for Soulfire Grand Master for me. The mana cost is a bit intimidating, but spells-matter and creature-light decks are going to be happy to see this guy.
I don't think Soulherder is better than Brago, but it is better than Venser. It costs 3 instead of 5, and doesn't have to worry about getting attacked. It also grows faster if you have Brago or other blink effects. I could potentially run all 3, but I'll be dropping Venser for the time being.
I also missed ETBT. Stupid keywords with random extra baggage. I still think it's a playable card, especially if some form of Ninjutsu ends up getting played.
I don't have enough big artifact bombs to support Tinker currently, and Puresteel Angel is definitely a bomb. I also happen to run 8 colored artifacts for it to hit. It may end up being too strong, but it's hard to resist trying.
Unicycle is more interesting than Lightning Greaves, and has enough board impact to see a lot more play in aggro. I expect the common play pattern to be crewing it with an existing creature the turn it's played, and then either crewing with a new creature or equipping on a new creature on subsequent turns, so that it gets much more value.
Growth Charm is playable combat trick and a much better Regrowth, which are both things I'm happy to see.
Generated Horizons is a simple, slow ramp engine. It might not last since it takes a while to pay off.
Vazal, the Compleat is a very fun-looking green fatty. The body is fine by itself, and I don't know what shenanigans it's going to enable.
Kykar, Wind's Fury
Maybe test at some point:
Rotting Regisaur
Knight of the Ebon Legion
Voracious Hydra
Cloudkin Seer