Final Fantasy IV
Final Fantasy IV, formerly known as Final Fantasy II in its initial western SNES release, is a role-playing video game published and developed by Square in 1991.
Introducing characters with preset classes, a focus on story and cinematic events, and the Active Time Battle system, where the battle progresses as time goes on instead of by turns, it largely influenced the course of future FF games.
An Easy Type version was later released, partially based on the much easier and simplified American release.
Hacking Tools
Standard
FF4kster
FF4kster by Pinkpuff is a tool created to be an all-in-one hacking suite for Final Fantasy IV (specifically, FF2US v1.1).
Deprecated
FF4ed
FF4ed is a tool by Yousei that serves as an extensive editor for the 1.0 version of the game.
FF2us Multi Editor
FF2us Multi Editor by JCE3000GT edits the properties of characters, magic, monsters, items, treasure and maps.
Zyrthofar's FF4 ROM Editor
Zyrthofar Blackcloak's FF4 ROM Editor is a data editor (enemies, spells, items, dialogues), however it is very buggy and hasn't been updated since 2005.
FF4Tools
FF4Tools by Phoenix Hacks are a set of Javascript tools created to be used alongside a hex editor to aid in hacking FF4. It can convert Dialogue, Events and Location Maps and convert it to hex, to be inserted in the ROM of your choosing.
Notable ROM Hacks
Namingway Edition and Project II
A pair of re-translation patches for the game, Project II by vivify93 serving as an improvement of FFII to be closer to the original FFIV whilst also having bug fixes. Namingway Edition by Rodimus Primal goes further by making it as close to the Japanese HardType version localized in English as possible.
Free Enterprise
An open world randomizer for Final Fantasy IV by b0ardface, riversmccown, and SchalaKitty, with code and programming assistance by Myself086, Myria, and Crow. Extremely popular for speedrunners.
Final Fantasy IV Ultima
An improved version of Final Fantasy II by 8-bit fan that merely adds new content to the game, rather than altering its feel.
The Darkness Within
A remaster of sorts by Rynzer that rebalances and redesigns the original game.
Unprecedented Crisis
A tech demo hack by Pinkpuff created to showcase the features of FF4kster. Starts slow with mostly gameplay edits, but later starts to heavily change the story.