PICO-8 - Lua-based fantasy console for making and playing tiny, computer games and programs.
8bitworkshop - Online IDE for Atari 2600 development based on Javatari.
TIC-80 - TIC-80 is a fantasy computer where you can make, play and share tiny games.
Pyxel - Retro game engine for Python inspired by fantasy consoles.
LowRes NX - Make your own games in BASIC on the LowRes NX fantasy console
LIKO-12 - Fantasy console built with the Love 2D game engine.