Emulators

Just click on the name, it has a direct link lol enjoy

MelonDS: DS emulator

mGBA: Open-source Game Boy Advance emulator

Mesen: Multi-system emulator. Supports NES, SNES, Game Boy Color, Game Boy Advance, PC Engine, GameGear and Wonder Swam Color

PCSX2: Open-source PS2 emulator (you need to get a PS2 BIOS to emulate pirated ROMs. You can get them on the official PS website)

RPCS3 Open-source PS2 emulator

PPSSPP PSP emulator

ReMEXA Modern Java reimplementation and host runtime for SoftBank MEXA S-Appli, Vodafone V-Appli, and J-SKY V-Appli software. ReMEXA focuses on preserving and running Japanese feature-phone appli on modern desktop systems.

Vimm's Lair: Emulation Lair Here you can find other emulators

ROMs

Vimm's Lair: The VaultThe Vault contains almost every game released in the world for thirty-four classic systems

RetroGameNexus: Hundreds of retro games

Internet Archive Just search for the game