A long romhacking idea I had was to hack FF1 (and possibly also FF2 and FF3) so that it/they uses compressed graphics (probably using Huffman compression) in order to free up lots of ROM space that could be used by further hacks or translations. It's more a proof-of-concept than an interesting hack by itself.
However in order to do this I need to store the decompressing routine somewhere, and guess what ? There's almost no free space in FF1 US ROM. I'm fairly sure however that there was this big ugly pseudo-random-number generator eating lots of ROM, and that someone had already replaced it by something very efficient. This could create some free space in the ROM so that I can insert some decompression code.
I'm almost certain this was already made, but I cannot find the hack here, probably it was just part of a bigger hack ? Where can I find this hack that replaces the PRNG with something more space-efficient, and free lots of ROM in the fixed bank ?