This mod gives you every achievement in the game upon entering this command: /achievementsall. This mod should be used for creative purposes only, and not to cheat. NOTE: Achievements such as 'a balanced diet' have actual counters and do not work with this mod, as it is too hard to change these hard-locked variables. Every other achievement works.
Creator's Note: This mod is useless now, since a command in Vanilla does the same thing even better, just use /advancement grant @s everything.