SMB Utility - This is the most amazing SMB editor yet.
Lunar Magic - Lunar Magic is a level editor created for Super Mario World.
Cheat Engine - Cheat Engine is an open source memory scanner/hex editor/debugger for Windows.
CoSMOS - CoSMOS is a Advanced Memory Scanner and Gamehacking Tool
GameGuardian - Play games your way! “GameGuardian” is a game hack/alteration tool.
WeMod - Personalize your gaming experience Thousands of free mods and trainers for your favorite single-player PC games — all in one place.