The Sims 4 Mod Manager :D !
Soooo glad this came out with out it I would have a hard time dealing with my mods in game.
Being able to make sub categories for my mods is amazing. I can make a folder specifically for holiday stuff, hair, makeup, clothes ,etc. The mod manager allows you to disable what you don't want in the game at the time or remove it. It creates a back up folder for your mods so if you delete by accident you are fine.You can open the main mod folder from it and add mods to it.
I'm looking forward to see what kind of updates will be added to it. Thanks to Raxdiam my Sims 4 experience is so much better because i can be so scattered with my mods.
Here is a link to download and it shows you in detail how to use by the creator.
http://raxdiam.com/ts4mm/
http://www.modthesims.info/download.php?t=534991
I made a short video showing what it can .