Workshop mods...

[Yuen]

Are there any workshop mods that are must-haves?

[Shazza]

Quick_SaveLoad- wait, that's vanilla now.

Manual Bed Assignments- ..that one literally just went vanilla like two nights ago!

"Must have" is gonna depend on exactly what you want. Coral's Customizations opens up PCC (player character customization) options and has some sub-mods.

If you want to reduce the grind time-wise there's Experience Multiplier and TpSleepRecipeX10.

KK Unlimited Stethoscope I'd say is a must-have for playing with allies, stethos (from Farris) are stupidly expensive consumables that let you view the detailed character sheet of your allies (to see what skills they have or don't, without having to crossref specific RNG skillbooks you may or may not have).

Give It Back also removes the negative Karma hit for trading items off an Ally (even simply swapping their gear).

KK Let's Talk More removes the negative Affinity penalty vanilla has for talking to someone more than a few times.

Tp Stackable Tools and Books are.. situationally good. The main issue with these two is that you can't Split a modded stack of items, leading to scenarios like buying fire/coldproof blankets autostacking and being unable to give them to allies without some serious finagling, and offerings to Itzpaltz becoming significantly slower because ancient texts will stack together.

And, if you want a massively detailed tooltip for allies/the world/enemies that includes things like their stats, exact resistances, your skill vs. the skill requirement of a hovered-over harvestable, there's GanExtendDisplay.

[internetgrout]

Autoexplore. You can vary what it does by what you hold, so strip mine or just kill enemies.

[rubish 1]

i like the infinite spell mod for a nicer just mana wizard feel

[meromex]

it all depends on what you like, i use:
KK Unlimited Stethoscope
auto explore since its cuts down the grinding
auto continue mining as well
the quest timer countdown so i know how much time i have in music/farm quest
Say Piety After Offered so i know what level i man with my god
i do use better tax evasion since i found the regular tax a tad high
only loose karma on caught since i think it disincentives you to steal otherwise
compare equipment
sell price (so i know what things cost on the tooltip)
and the canisminor portrait and pcc mods

[Hod and vampire co]

I like easy farming for the extra seed and a little extra EXP on harvest
also the bank interest since it makes paying off and keeping up with taxes a bit easier if you want to do less profitable activities for a while without having to worry about debt