>>33278984Brown and Prism are a must. The former is one of the oldest "worthwhile" hacks" and the latter is a decade-long-made labor of love sequel.
Gaia is a really impressive beta and actually has real, fully-functional Mega Evolution, on top of implementing a ton of later-Gen Pokémon with their proper abilities and gimmicks and such. It's been a while since that beta and I don't pay attention to Gen 3 enough to see if any other hacks have used that Mega Evolution code.
I'm admittedly biased toward Gen 1 and 2 hacks. Maize is a cool beta especially since its latest beta was done traditionally (it's since been ported to disassembly but nothing new has been released with that), and Red++ and Polished Crystal are both well-done Gen 1 and 2 modernization hacks and the latter adds a lot of custom content.
