Here's the list. And the key for this list:
Green means it's already TMC-style.
Blue means it's easily editable to be in TMC style.
Yellow suggests other possible ways of doing this foe.
Red requires customs from scratch.
* = not taken yet.
x = claimed; W.I.P.
X = completed and submitted.
Bolded enemies come in multiple varieties, each holding different enemies.
Minibosses:
* Rolling Bones
* Hinox
* Dodongo Worm
* Cueball
* Stalfos Warrior
* Smasher
* Grim Creeper
* Vire
* Blaino
* Stone Hinox
* Large Buzz Blob
* Gohma - use FSA-styled sprites, if possible?
Non-dungeon Guardians:
* Great Moblin
* Large Armos Knight
* Turtle Rock Turtle
NIGHTMAREs:
* Moldorm - Use FSA-styled sprites, if possible?
* Genie in a Bottle
* Slime Eyes
* Angler Fish
* Catfish / Slime Worm
* Fascade
* Evil Eagle
* Hothead
* Giant Hardhat Beetle
FINAL:
* Shadow Zol
* Shadow Moldorm - Use FSA-styled sprites, if possible?
* Shadow Agahnim
* Shadow Ganon
* Shadow Lanmola
* Dethl
Have at it.