There are many different variants to personalize the post-apocalyptic world to the one that best meets your taste, so if you want to build settlements that are unlikely to be large, have Dogmeat by your side with a regular friend, or just make the wasteland look a little less ... Waste, then these mods are the good reason to explore Fallout 4 again.
SimpleSeasons
Given the flashes of color sometimes seen in Fallout 4, you can't deny you'll finally get fed up with the wasteland's dreary yellows and browns. SimpleSeasons turns all of that into a banquet for the eyes by transforming the dystopian world (but not the senses that someone with hayfever would be able to hear). These four mods-you don't have to download them all if you don't want to, by the way-either cover the desert in snow, spring up lush greenery, transform it into a cloud of oranges and yellows, or produce green trees that just start turning yellow. Now if only a video mode existed to catch all that elegance …
Any Mod Any Weapon
Neglect about the base game's weapons manufacturing limitations, the Any Mod Any Gun mod will let your mind run wild while you're at the workbench. Would you ever like to fire cannon balls from a handheld revolver, build an electrified mini gun or fire a Deathclaw's claw on a boxing glove? Anything achievable with this mod.
Everyone's Best Friend (Dogmeat + Companion At Same Time)
Dogmeat is a distinguished companion. There's no doubt that He's A Very Nice Boy, Yes He Is, but he's not influenced by a variety of companion benefits: Live and Love does not extend to the doggo, and he doesn't disable Lone Wanderer perk benefits. This mod allows instant possession of Dogmeat and another pet. Security in numbers, right?
OCDecorator
After all, you can just do what your mum asked you to do and clean up after yourself. The OCDecorator mod allows you to put any item on any other item and it is no longer a complete nightmare to put arms and guns on shelves or office fans on desks. Now you'll have anything neatly arranged in your city, secured in place, and shown beautifully instead of getting it all knocked over by NPCs and ending up in a mess on the floor.
Place Anywhere/Everywhere
The Vanilla Settlement Editor for Fallout 4 is not the right one. Walls often don't match up, you get things and furniture that just can't be put where you want, and you wound up with some hideous holes (and even worse, defenses) in your decorative structures. The Place Anywhere / Everywhere mod gives you the power to clip onto certain items so you can match it neatly together. No more lacunae, no more mess.
Want more info on mods in Fallout 4? Make sure you check the full list with The Top 7 Mods You Should Have on Your Fallout 4 Load Order.