We've covered many ROM hacks in the past, mostly Pokémon ROM Hacks, seeing as they're incredibly popular nowadays, and for good reason; some of them are remarkable games, such as Pokémon Unbound and Pokémon Lazarus.
But finding them, understanding if the community likes them via reviews, and what type of features they have is a little bit cumbersome if your favourite retro gaming website doesn't cover them, and that's not to mention filtering through some very dodgy websites to acquire them... usually illegally.
Today, I stumbled across a website called HackDex, a simple, well-organised website that showcases the most popular ROM hacks on the market. It offers the ability to patch your own obtain ROM files legally, shows what type of features each ROM hack offers, for example, Pokémon Too Many Types 2 has "custom types, custom moves, Mega Evolutions, is based on Pokémon Emerald and HackDex even shows you how many downloads the game has, reviews and the ability to follow the developers behind them.

What HackDex is really known for is the ability to upload your own legally-sourced ROM files from your cartridges by using something like the Epilogue GB Operator, and then allowing HackDex to legally patch your game into a community-made ROM hack, instead of downloading an entire new file from a random website, which comes with obvious risks.
For example, I uploaded my official Pokémon Yellow ROM file from my cartridge, and it gave me the ability to patch it into two different Pokémon ROM hacks with a simple press of a download button.

You can do this with most retro Pokémon games, such as Pokémon Red/Blue, Gold/Silver, Emerald/Ruby/Sapphire, Pokémon Pinball, White/Black, Heart Gold/Soul Silver and a lot more.
It's as simple as uploading your ROM file, patching, and then inserting the file onto your handheld/PC/console to start playing. It's now my go to soure for finding ROM hacks legally.
So, put simply, Hackdex is a community hub for discovering Pokémon ROM hacks (exclusively for now). It centralises ROM hack discovery and provides a legal, in-browser patching system to play ROM hacks safely and easily.

You won't find complete, downloadable ROM hacks here; they focus on legal distribution by hosting and sharing "patches" rather than complete ROM hack files. You are 100% responsible for obtaining your own base ROMs legally, typically by extracting them from your cartridges using accessories.
If you are a developer of your own ROM hack, you can submit your own to be reviewed, and if accepted, it will be uploaded to HackDex for many retro gamers to discover and download. I honestly wish I had known about this website sooner. It's great, visit HackDex today to discover new Pokémon ROM hacks.