Pokemon ROM Hacks by Platform

GBA (Game Boy Advance) - Gen 3 classics. FireRed, Emerald, Ruby/Sapphire base. Most popular platform for ROM hacking.

NDS (Nintendo DS) - Gen 4/5 games. Platinum, HeartGold/SoulSilver, Black/White base. Advanced graphics and features.

3DS (Nintendo 3DS) - Gen 6/7 games. X/Y, ORAS, Sun/Moon base. Modern engine with 3D graphics.