You have the tag 1.13 so I assume you mean 1.13 mods? If you want to get mods from a safe site and large scope, use Curseforge, for 1.13 modding use the Rift modloader. If you want 1.12.2 or under mods which is a bigger scope of mods, you use Forge. Its up to you of course what you are looking for really.
I document and update the Rift Discussion thread to state 1.13 & 1.13.2 supported mods from Curseforge for safe mod usage, searching and installing so I know what I'm talking about or else I'd really be dreading things or not commenting about 1.13 modding confidently. I as well as many other Youtubers since I won't take all the credit, have mod spotlights and tutorials on how to do 1.13 modding properly. I on the thread document mods for 1.13 & 1.13.2 with mod lists, recognisable mods for these versions, have tutorials for how to install Rift for 1.13 with the Vanilla, MultiMC5 & Twitch Launchers and 1.13.2 with Vanilla Launcher so far, mention Rift & Datapack conflicts, I get as deep as I can. I would like help with documenting these but I'm doing ok so far I guess while others do videos, I created the thread to help people out and I also update the thread often as well as do my own videos on the subject matter for mod spotlights, install tutorials and datapacks/Rift & datapack conflicts or the 1.13.2 mod list I updated recently.
I shouted out a Youtuber's Rift mod video, so I don't take credit for youtubers that upload videos on how to install mods or what people are available for Rift with spotlights or videos covering them, I inform information about 1.13 mods for the players if they choose to use it in the thread I focus on, its up to the player if they want to use the mods or not, I just give them the info. The Youtubers don't help me out directly I just found their video one day and gave them credit in my thread with an update post for what I found in that the video I found that they made that shows off the mod which was the case with Aether Legacy Rift Edition which I wouldn't have known the mod supported Rift if it weren't for that video by a particular Youtuber 'Craft Stones', and also confirming about the mod's 1.13 state with the creator themselves on Curseforge.
Rift Modloader (for 1.13 mods, not 1.13.2, the links to that are different to find, use Aquarius or Voxel Map's mod pages for the 1.13.2 version of Rift. They support Rift for 1.13.2 at the moment, only the two of them. At least to my knowledge anyways)
Mods that Curseforge filters to state what works with Rift over mods that don't use Rift and could state that they are for 1.13 and don't support Rift. This will make it easier to tell what is Rift supported and never get it wrong unless you filter it again somehow, so this is the fool proof enough direction of mods if you really want to use them in 1.13:
If you want 1.12.2 mods or a bigger modding scope compared to 1.13, then obviously there are plenty of people that have videos, or help on 1.12.2 these days that can do a better job than I could.
I hope that helped out, if you want 1.13 mods, follow along with those links or my thread on the 1.13 or 1.13.2 mods/Rift modloader. I'm not shouting myself out, I'm not even the creator of Rift, just someone providing the information to the players who choose to use it or getting curious about Forge 1.13 or safe 1.13 mod searching. Thats all. Good luck with your modding fun.