The only tools I actually use at the moment are the hex editor HxD, and the python builds for compiling things, and the new PGE for Emerald.
Personally I would swap to Emerald anyway, there's no limited functionality over Fire Red to be honest. I would say the only thing thats in Fire Red and not Emerald is the dynamic OW hack, which admittedly is awesome, but will be ported by us eventually.