EmuNations

MelonDS is a Nintendo DS emulator aiming for better performance while being able to to emulate Wi-Fi and local multiplayer capabilities. It has many quality of life features such as save states, Joystic support, screen positioning, RTC, microphone and much more..! It's developed by a former contributor of DeSmuME and even has libretro core available. There's also active development of an Android port.

It also requires DS BIOS/firmware copies

• bios7.bin, 16KB: ARM7 BIOS

• bios9.bin, 4KB: ARM9 BIOS

• firmware.bin, 128/256/512KB: firmware

Please note firmware boot requires a firmware dump from an original DS or DS Lite. DS firmwares dumped from a DSi or 3DS aren't bootable and only contain configuration data, thus they are only suitable when booting games directly.

DeSmuME is an open-source Nintendo DS emulator and is among the most accurate. It sports tools designed for hackers, speedrunners, youtubers, and casual gamers (use Dev-builds). Homebrew programs are supported and can even be debugged through GDB. It can be run from the command line directly or as a graphical program and it even allows for increasing internal resolution. It is also available as a libretro core for RetroArch.

DeSmuME X432r is a modified version that has filters, OpenGL video setting, 3D emulation, rotate screen, up scale resultions and much more but requires a higher end PC and hasnt't been updated since 2015.

NooDS is an open-source Nintendo DS and GBA emulator with the goal of being fast and portable. It's currently available for Linux, macOS, Windows, and the Nintendo Switch. 

That said, it doesn't provide high-level emulation of the BIOS yet. To actually run games, you'll need BIOS files (bios7.bin and bios9.bin) and firmware (firmware.bin) placed in the same directory as the executable. On the Switch, you'll also need to have a ROM file (rom.nds) in the directory.