Lump them all in here with Neoform, which is basically a one-shot Birthing Pod activation in the form of a cheap Simic card
I wasnt sure what to make of Tomb of Horrors Adventurer when I saw it, and Im still not sure now
Where Mai really shines, however, is against Combo decks
Finally, the ultimate isn't even good all the timeif you are winning and have a decent board, you might want to keep your own permanents rather than take your opponent's, especially since Aminatou, the Fateshifter is more about synergy than raw power, so your cards will likely be more valuable to your deck than your opponent's cards
Legendary Planeswalker - Nixilis
The untap symbol in an activation cost means Untap this permanent. A permanent thats already untapped cant be untapped again to pay the cost