EmuNations

Flycast is a SEGA Dreamcast, NAOMI and AtomisWave emulator which was forked from Reicast. It's well regarded and supports multiples peripherals, texture upscaling, widescreen, Dreamcast Live fan servers and much more...

RomVault is a GUI-based rom management tool and can be seen as an alternative to Clrmame Pro with additional features at managing large numbers of DAT and/or Roms in a more streamlined process.

No$GBA is currently the fastest working GBA emulator, though not the most accurate on GBA and even less on DS. It supports multiplayer and is able to load multiple GBA/NDS ROM files for linking games...