Yeah, but I don't know what you'd be looking for.
A lot are useful just to get rid of pesky bugs.
A lot are game rebalancing mods, or even story mods, and the main focus of romhacking.net has always been translation patches for games filthy gaijin didn't get, and a lot of these are also sold by cartridge reproduction sites, but if you really just want the game buy it off aliexpress like everyone else, only in very rare cases does the original creator of the mod get any money from this.
I'll post some more up, but not too much
Remember when I posted about MSU1 patches? The patches that give SNES game PCM sound? The ones that aren't Super Road Blaster or Super Boss Gaiden that actually add content are the BS (Broadcast Satellite) Legend of Zelda games, which was a version of the original Zeruda no Densetsu remade for the Super Famicom and only broadcast one week at a time in Japan. (I suppose if you were in the footprint of the satellite you could have picked it up anywhere, but to my knowledge only nihonjin played them at the time)
What's really interesting about this is that because someone recorded a gameplay video onto his VCR at the time, there are fandubs for the BS Legend of Zelda games based upon this, which are translations of the original narration. (You can play MSU1 games on real hardware if you have an Everdrive model flash cartridge. You can buy clones of these off ali; I typically use my Wii and an SNES controller, or a DualShock4 on my tablet on the go)
More information here
Going on with information about Final Fantasy games, there is a
retranslation of Final Fantasy 7, a
very nice hack + translation of a Chinese original pirate port of FF7 to the NES;
a hack of FF8 that re-enables PocketStation content; and here's a
hack of FF9 that makes Excalibur II less frustrating to get.
There are also ROM hacks out there that just patch the game in order for it to run on other systems; for instance, the SG 1000 and the ColecoVision are similar enough in architecture for software from these to be run on the MSX, with hacking.
This is an example on romhacking.net;
this is an example of a company that essentially ports games from the MSX to the Coleco, sometimes requiring their own proprietary hardware to make it boot - at which point IMO you may as well just import an MSX from Japan or whatever and play it that way.
A point must be made for certain "full color" versions of Game Boy games. I think this is pretty interesting and I point out
this one, which is a full color version of Super Mario Land 2. ONLY for Game Boy Color; it won't boot on a DMG, but at that point, you should just play the vanilla version!
Here is what I believe to be a colorization of Kid Icarus;
here is a full color mod for Pokemon Red.
Another point must also be brought up: due to the similarities in hardware between the Game Gear and Master System (GG pretty much just has an expanded color palette) there are hacks of GG games to make them able to be played on a Master System/SEGA Mega Drive.
Here is a list of them; there were also a LOT done BITD by game companies who published for SEGA, since the Master System was a big seller in Europe and Brasil. If you're emulating, stay away from all of them, but if you're using a flashcart/game copier on your Mega Drive, go right ahead. The Everdrive and MEGA SD don't require a Power Base Converter to play Master System games; I don't know about game copiers.
Also there are a lot of crappy hacks out there that do nothing but just turn all the player characters into giant penises. baddesthacks.net is what you want if you want these. They do have the credit for posting a translation patch for Shin Megami Tensei If because Gideon Zhi never got off his ass to bother to do it, instead "reserving" it for more than a decade.
