Sticking with suggesting mods I have actually tried, with one exception. I have actually been studiously avoiding Stardew Valley Expanded and Ridgeside Village as the Juggernauts, though they are easy ways to sdd a bit of everything.
I start with my 5 top recs:
-Automatic Gates
-NPC locations
-Better ranching (shows if your animals need petting, milking, and shearing)
-Canon Friendly Dialogue Expansion - covers EVERYONE in one shot.
-Diverse Stardew Valley (technically this is now 13 smaller mods instead of one big one but Moddrop lets you download them as a bundle.) Visual changes to almost everyone, configurable.
For Quality of life, I also use:
-Bigger Backpack
-Skull cavern elevator (you can do this on an honour system and not use it till you made 100 on your own and call it a reward.)
-Multiple Mini obelisks
-Submerged crab pots (when the crab pots have bait or harvestables on them, all you see is a bobber. It trades off not knowing exactly what is caught in advance for less visual disruption.)
-Trash doesn't consume bait. (for both fishing and crab pots. More useful early game.)
-GenericModConfigMenu (if a mod has different configurable bits, this gives you a menu on the load screen where you can make the changes, instead of having to dig into each config file. Really only matters if you use a lot of configurable mods)
For NPC relations:
-Ranch Expansion (Gives Marnie and Jas some extra events and even Shane gets a bit more dialogue. Give Jas a cat.)
-Date night. Your spouse invites you on dates on occasion. Some are the same for any spouse, some are personalized.
-Mal's Seb expansion. Gives Sebastian a post marriage plot arc. Only relevant if you marry Sebastian.
-Free Love - lets you marry more than one person. There's also a multiple spouse dialogues mod that has them interact with each other a bit more, and I honestly don't remember now where one ends and the other begins.
-Platonic Partners and Friendships. Lets you get more platonic variants of the 10 heart events with bachelors and bachelorettes you want to be friends with but don't want to date.
-Life cycle -Rival Hearts: lets various townsfolk you aren't dating have possible romances with each other, in some cases including marriage and kids. Is very hetero, with only one f/f pairing and no m/m, but other rival hearts mods include Penny/Maru and Sam/Sebastian.
I haven't delved much into new NPCs.
-I like Professor Jasper a lot.
-I liked The personality work and events done on the Stray Catfe but it's abandoned forever in beta, which is frustrating.
-If you like cats, I'd suggest either Mister Ginger (turns Jas's cat into a giftable NPC, though his dialogue is mostly prrrr, mreow, hisss, etc, at first) OR Jorts and Jean the Helper cats. (yes, that Jorts and Jean. Unlike Mr. Ginger they talk, though...). Maybe not everyone wants friendable cats, but both are better done than I'd expect for silly cat mods. Their lore - and art style - clashes slightly despite the best efforts of both mod makers to integrate them.
-If you want basic visual tweaks, it makes sense to start with Elle's various animal and seasonal mods, which are small but not insignificant. Or look at people's modded images and pick your favourites.
I haven't haven't done any crop or animal mods yet and my only recipe mod add-ons were Tea Time (because tea) and Forsy's comfort foods, which I picked because there should be strawberry recipes, dammit. It's a bit overpowered in its buffs, though.
