I play with

TargetPortal so I don't need a gigantic portal hub to travel in the world
PlantEverything because I like how it helps you build nice landscaping
FuelEternal because I don't want to refill my fires/torches on big builds
EquipmentAndQuickSlots because it cleans up my inventory by moving clothing to a different panel
AzuClock it's nice to know what time it is
FarmGrid and MassFraming to easily plant things
More_Gates to have access to more windows/gates/drawbridges/etc
CraftFromContainers so I can build stuff without moving mats in my inventory

Most of these are QoL, with maybe the exception of TargetPortal which modifies a game mechanic.

This video goes over some pretty interesting/wild mods: https://www.youtube.com/watch?v=bHvOJmUA2rU