Here you can see a list of recommended, accepted and banned emulators. If your emulator doesn't appear in any list, it may still be accepted.

Accepted

NES

Nestopia (recommended)
FCEUX (recommended)
PuNES (recommended)
BizHawk
FCE Ultra

SNES

higan v094
BizHawk
lsnes
Snes9x

GB/GBC

Gambatte (recommended)
bgb (recommended)
BizHawk

GBA

BizHawk
Visual Boy Advance

Wonderswan

BizHawk

DS

DeSmuME

Sega Master System/Game Gear

Fusion
BizHawk

Mega Drive/Sega Genesis

BizHawk
Gens

N64

BizHawk

PS1

ePSXe 1.9.0 (recommended)

PSP

PPSSPP

Sega Saturn

BizHawk

GC

Dolphin

Wii

Dolphin

Banned

NES

Fantasia

SNES

ZSNES

GB/GBC

Visual Boy Advance (VBA)
VBA-M

Sega Saturn

Yabause