What are some of your TS4 favorite mods?

I would also recommend starting on Curseforge, it's easy, safe and just as easy to delete if you should change your mind. Some of my absolute must-play mods: 

• MCCC (a given that reduced the need for many other mods)
• Home Regions (already mentioned, and also available on CF) - so important for immersion, at least for me. 
• Better Build Buy and Tool from Twistedmexi (on CF but usually updated faster on their Patron) 
• Sleep all night from LMS - it's such a small thing, but to not have sims wake up three times a night makes playing so much more realistic. 
• no autonomous phone and no autonomous wash dish after eating by bienchen (on their website here) - makes dining as a family so much nicer. 
• If you have dine out Carls dine-out mod is an absolute must. Restaurants are more or less unplayable without it. 

I also use a lot others of LMS and Bienchen, too many to mention, but both are great creators of relatively small mods that rarely break, and LMS is so fast in updating and has all her mods on CF which makes it easy.