for me personally, as few as possible, purely to ensure that playthroughs last a decent amount of time.
for 1.0 b333 ie vanilla, ie for "serious/proper playthroughs" i use only these ~
F:\games\7 Days to Die\7.Days.to.Die.v1.0.(b333).Stable\Mods
7D2D World Lighting Tuned (v1.0)
AGF-A20HUDPlus-EPatch1.0.1
AGF-A21HUDPlus-Addon1.4.0
AGF-A21HUDPlus1.8.0
donovan-longerlootbags
KHA21-HPBars
KHV1-WanderingHordeFrequency (1.0)
VanillaFoodModel (v1.0)
WMMSkipNewsScreen-5520-1-0-333-1-1722026489 (1.0)
...not to make the games easier or quicker, i just those for quality of life ie they complement/add missing QOL things but don't detract from the playthroughs (i'm not suggesting other peoples' suggestions detract obviously).
i do use other mods but it depends on what overhaul mod i'm playing, for example i like the Guppy zombie models, but for separate playthroughs ~
7.Days.to.Die.a21.2.(b37).Hotfix
7.Days.to.Die.a21.2.(b37).Hotfix.with.Joke.Mod
7.Days.to.Die.a21.2.(b37).Hotfix.with.Outback.Roadies.Mod
7.Days.to.Die.a21.2.(b37).Hotfix.with.Preppocalypse.Mod
7.Days.to.Die.a21.2.(b37).Hotfix.with.Random.Wandering.Hordes.Mod
7.Days.to.Die.a21.2.(b37).Hotfix.with.Wild.West.Mod
7.Days.to.Die.v1.0.(b316).EXP.b317.Hotfix.with.Guppy.Zombies
One other example is that before we had lockable inventory slots i used KhaineGB's mod for that, then The Fun Pimps kindly added their lockable slots so i didn't need to use that anymore (to me lockable slots are is an important quality of life mod)
I frequently check out the modding sites but for me personally, like i say, for vanilla, i only like to have things that complement the game, in the game, and for 99.9% of other mods, i can just install them inside a separate overhaul mod, or a separate copy of vanilla (for instance if i'm going out for a night out and have a couple hours beforehand where i just want to mess about in the game, i can fire up one of the other overhauls and just have non-serious crazy zombie slaughtering fun for a while) . just my 2 cents