Flycast is a SEGA Dreamcast, NAOMI and AtomisWave emulator, forked from reicast, and made by flyinghead.
Reicast is a Sega Dreamcast emulator primarily aims for speed and to run on PC and Android. It is derived from the nullDC codebase.
Redream is a work-in-progress Dreamcast emulator, enabling you to play your favorite Dreamcast games in high-definition on Windows, Mac and Linux.
DEmul is a Sega Dreamcast, NAOMI, NAOMI 2 and Atomiswave emulator for Windows, developed by Wind, DreamZzz, MetalliC, ajax16384 and CaH4e3.
nullDC is an open source Sega Dreamcast and NAOMI emulator for Windows, developed by drk||Raziel (currently under the nickname skmp) and ZeZu.