Cast Down

Crocanura

Reach (This creature can block creatures with flying.)
Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Spined Karok

Arbor Elf

Fyndhorn Elves

Emperor Crocodile

When you control no other creatures, sacrifice Emperor Crocodile.

Lurking Crocodile

Bloodthirst 1 (If an opponent was dealt damage this turn, this creature enters with a +1/+1 counter on it.)
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Catacomb Crocodile

Stonefare Crocodile

{2}{B}: Stonefare Crocodile gains lifelink until end of turn. (Damage dealt by this creature also causes you to gain that much life.)