Aqua Glob - Awesome
Grasslands - Is alright, I guess. SkeletonWreck.
Wormhole - NO! LYSOL. NEVER. NEVER MAKE SUCH CARDS! THEY'RE SO OP IT'S ROOFTHROUGH!
Healing Sprigns - OP. Wrecks any poison deck set against you. Aside from that, a SoD. If you made it 1-2 poison per turn, then it'd be alright, but 5?
Rancor - Is alright with the cost.
Wrackhorn - Too cheap for this price. So far, creatures with Dive:
-cost 4, both of them
-Wyrm's dive costs 2, Pegasus' costs 1
-And they have stats like 3/3 and 3/2, while this one has 4/5.
Kick the cost up to 6-7 and it'll be alright, or 5 cost + 2 per dive.
Shish - Vampire costs 5 and is 4/3, this costs 4 and is 5/5. Think of the balance.
Firefly King - Seahorse males don't breed, they just carry babies that the female lays as eggs in the male's bellypouch. Also, Firefly Queens mate with random males of their kind, and possibly eat them afterwards, not have stable kings. But oh well. The effect could be deadly, with EFFs getting to 5/3 or further, luckily the King has just 3 HP and is Paradoxable, so he won;t be living long.