Choose an editor
Episode I & II and Episode III use completely different save formats, so each has its own editor. Pick whichever matches the game the save came from.
Episode I & II →
GameCube (.gci) and Dreamcast (.vms, or a whole VMU memory card image). Edit name, class, section ID, level, experience, meseta, stats, inventory and bank.
Episode III: C.A.R.D. Revolution →
GameCube only (PSO3_SYSTEM + PSO3_CHARACTER). Edit the card collection, build and reorder decks, and browse every card with its stats, abilities and attack range.
Not sure which you have? Episode III saves are named PSO3_… on the memory card; Episodes I & II use PSO_… instead.
Don't have a save file yet?
How to get a save off a real GameCube — GCMM/Swiss, and how to get homebrew running in the first place.
How to get a save off a real Dreamcast — Brook Wingman SD, DreamShell, or dcdrop over a Broadband Adapter.