DeSmuME - DeSmuME is a freeware emulator for the NDS roms & Nintendo DS Lite games created by YopYop156.
melonDS - A Nintendo DS emulator with support for commercial games.
VisualBoyAdvance - VisualBoyAdvance (VBA) is a free software (GNU GPL) emulator targeted for the Game Boy, Super Game...
RetroArch - RetroArch is a frontend for emulators, game engines and media players.
Drastic - Drastic is a Android DS Emulator
mGBA - mGBA is an open source emulator of the Game Boy Advance. The goals are speed and accuracy.