There are some very useful tools that the RBO forum communities created, such as :

Translates most of the game's interface, menus, and some in-game text (skill usage and background character dialogue).
NOTE: Install RBO EX3 scenario before patching/using.
Allows viewing and extracting PAC file contents such as sprite sheets, background images, game music, and sound effects.
An advanced PacNyx that can be used to create and edit sprite images, character poses, and effects.
NOTE: Beta version, still in development
Previews a character's next-level experience requirement.
NOTE: Run it first before the RBO EX3 Scenario.
For planning purpose in allocate Stat Points and Skill Points, also list all the combo button for 3 Players, HP SP calculation, experimental Cost calculation.
Tool for changing player characters into any monster.
NOTE : Many monsters have bugged moves and cannot pass certain stages.
Can be used to change almost all game elements such as stage backgrounds, monsters, and sounds used in the game.
NOTE: Discontinued development until further notice.
Design to make RBO can be played on internet with other 2 Players.
NOTE: still in development