There's also this site https://www.save-editor.com/tools/rpg_tkool_mv.html (Do not visit that site without an ad blocker!)
It allows you to transform your .rpgsave files into .txt files, so you can edit them with a regular text editing program, and then convert them back. That one requires a lot of programing skills tho.
https://www.saveeditonline.com however is by far the best choice, but it takes some time to learn all the tricks and exploits.