Here's a review of the hacks I'd personally love to see:Monster Rancher (PSX)
A "Seasonal Shrine" hack similar to this (STARWIN, please come back): https://www.romhacking.net/hacks/3482/Monster Rancher 2 (PSX)
A bugfix regarding how to obtain Mock.Both of the above
A bugfix regarding the occasional loading screen lockout.Pokemon Red/Blue (GB)
Two different patches: one restoring the 39 missing alpha Pokemon like Gorochu, and the other being a graphical patch that replaces the in-game sprites with monochrome versions of the front and back sprites from FireRed and LeafGreen.Pokemon Yellow (GB)
A "Pokemon Brown Version: Special Eevee Edition" hack (with Eevee's voice clips from the Let's Go games on Switch)Mario Party 1, 2, and 3 (N64)
An "NSTC-U Voices" hack that uses voice clips from Mario Party 3, 4, and 5, as well as DK64.
And here's some more hacks I had in mind:Super Smash Bros. (N64)
An "Unlock All Characters" hack that makes Luigi, Ness, Captain Falcon, and Jigglypuff available from the start.Super Mario RPG: Legend of the Seven Stars (SNES)
A hack that adds Luigi as a sixth party member, instead of demoting him to "End Credits Cameo".Pokemon Emerald (GBA)
A "Pokemon Perfect Emerald" hack that not only allows you to get all 386 Pokemon, but also fixes some major bugs, restores the Sailor's original Japanese sprite, etc.Sonic the Hedgehog 3 & Knuckles (Genesis/MD)
A "Kirby in S3&K" Hack that replaces Knuckles with Meta Knight.Sonic the Hedgehog 2 (Genesis/MD)
A "Somari the Adventurer 2" hack that replaces Tails with a Somari-like Luigi.Pac-Man 2: The New Adventures (SNES)
A hack that replaces the Ms. Pac-Man game with the Pac Jr. game found in the Genesis port (complete with music changes).Pokemon HeartGold (DS)
A "Pokemon Throwback 2" hack that makes all 493 Pokemon available, replaces Lyra with Kris, makes the GB Sounds available from the start, and more.Super Mario Bros. (NES)
A "Super Mario Bros. 5: The Uncharted Lands" hack that picks up where The Undiscovered Zones left off.