Hi! Here's a cool list of mods for far cry 5 https://insider.games/best-far-cry-5-mods/ , but I understand that it is not complete?
In terms of gameplay mods, the only base mod you'll need is the Resistance Mod, found here. It comes with an installer that lets you cherry-pick from quite a list of mods, so you can customize your own gameplay experience.
If you're interested, you can try and create your own mods too. Pop in the Far Cry Modding Discord for more information.