Back on topic, I'm really liking these ideas. Very cool stuff.
King Parrot
Action - $3
Do this twice:
Play an Action card you have in play that isn't a King Parrot or a Duration card.
Early on, Adventures had a similar card that let you replay a card you had in play. The problem is that you usually need a village to make it worthwhile. Maybe doing it twice makes up for that, but I worry that King Parrot will be really strong in the cases where you do have a village available. It might just be too strong across the board.
Cats
Action - $4
Gain a Cats
Trash a card from your hand. Gain a card costing exactly $1 more than it.
Sort of a roundabout Rats/Feast. I mean it's similar in concept to Rats, but maybe different enough.
Toad
Action/Attack - $4
+$1
You may gain a Toad. If you did, each other player gains a Curse. Otherwise, return this to the supply.
Looks promising, although it has the potential to empty the Curses very quickly; even more quickly than Sea Hag. Obviously you're shooting yourself in the foot if you do so, but that doesn't mean it won't happen. Anyway there may be tweaks if that ends up being the case. I like the concept.
Tiger
Action - $4
+2 Cards
You may play an Action card that isn't a Tiger from your hand.
Very simple and very cool.
Dolphin
Action/Duration - $4
+2 Cards
If any other player has a Dolphin in play, +$1
At the start of your next turn, +1 Action
Neat. You might consider "Choose a player. +$1 per Dolphin he has in play." But maybe that's too much of a boost for the players that go Dolphin (in a game with more than 2 players). Cool idea in general.
Fish
Action/Duration - $2
+1 Action
+1 Buy
At the start of your next turn, you may return this to the supply. If you do, +$2
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While this is in play, when you would gain a card, you may instead gain a Fish.
Looks cool!