EmuNations

Redream is a closed-sourced Dreamcast emulator, enabling you to play your Dreamcast games in high-definition on Windows, Mac and Linux. There are 2 versions; lite and premium (small fee). The only significant difference is that the premium version lets you scale to Ultra-HD resolutions. With an excellent streamlined experience, it will eventually be the best, as accuracy continues to improve (passed 80%). That said, it's not the most accurate nor does it support Dreamcast peripherals but does have some support for WinCE games.

Note: BIOS file not required, but may improve compatibility in certain cases.

Flycast is a SEGA Dreamcast, NAOMI and AtomisWave emulator, forked from reicast, and made by flyinghead. It can emulate the standard Dreamcast controllers, Keyboard, Mouse, Light-Gun (with your mouse), Twin Sticks, and even the ASCII Mission Stick Emulating two expansion sockets per controller. Also has widescreen (Rendering outside of screen), texture upscaling, frame skipping dump textures and load custom textures. A Dreamcast BIOS file is optional, but NAOMI and Atomiswave BIOS files are required. It's also able to connect to Dreamcast Live fan servers. 

Current game support are the following:

• SEGA Dreamcast games (CHD, CDI, GDI, CUE) including games based on Windows CE

• SEGA NAOMI games (.zip, .7z, .dat/.lst)

• SEGA NAOMI GD-ROM games (.zip, .7z, .dat/.lst and .chd)

• Sammy Atomiswave games (.zip, .7z)

Noteworthy forks

• Flycast Dojo is derived from Reicast, with a focus on netplay features and replay.

It is an open-source Dreamcast emulator for Windows considered among the best in regards to accuracy. Its capable of running any Dreamcast game, even some none-commercial games. The graphics, sound, controllers and memory use a plug-in yet it can even play games burned to CD-ROMs. That said, initial setup can be quite tedious. 

Please note it has recently been resurrected by the original developer(s) and being rewritten in RUST, as such its (v2.x)  currently not as feature-rich as the previous version.

Note

• BIOS not provided. Use provided publicly-sourced BIOS

• Windows version 1.0.4 r150 contains the Shenmue fixes

Launcher

• NullDC-BEAR - Launcher and optimizer to ensure easy setup while optimizing settings for a smooth gameplay experiance.

DEmul is a very accurate emulator which is basically compatible with any commercial game available and can also emulate arcade hardware (Naomi 1, Naomi 2, Hikaru, and Atomiswave). They use a plug-in system, which can be quite tedious to initially configure and lacks good documentation so it’s not easy to set it up. It also has virtual memory card support to save game progress at any instance. 

Note: BIOS not provided. Use provided publicly-sourced BIOS

Deecy is an experimental, early-stage Sega Dreamcast emulator written in Zig, focused on accuracy and clean architecture rather than full game compatibility. It can boot and run a growing number of titles but remains highly incomplete, with many hardware features still being implemented. It’s mainly aimed at enthusiasts and developers interested in Dreamcast internals or emulator development rather than general users seeking a polished, fully compatible emulator.

This project is no longer active. The author recommended using another Dreamcast Emulator that is activelly developed, possibly a reicast derivative like flycast