The Rim of Madness and Call of Cthulu mods go together a suite to make different and exciting game. Androids can also be really fun. My favorite mods tend to be the ones that change how things work.
Mod switch: I cannot think of a reason to not have this mod. Mod Switch remembers your mod configuration and you can save multiple templates. You can have one loadout for Call of Cthulu one for Star Wars, and a thousand others depending on your preferences.
Power Switch: Power switches can now be set to turn on based on the time of day, proximity of friendly pawns, or proximity of hostile pawns. This helps you use power smarter, automatically unplug the workshop when nobody's awake to work, leave your turrets off until you need them, or disable lights until pawns are around to need them. Added bonus: underground conduits, put them wherever you want without uglying up your base.
Camera+ zoom in closer, zoom out further, you don't realize how much you needed it until you use it.
Silent doors: If you have more than one pawn and you don't want to go insane to the chorus of WOOSH WOOSH WOOSH you definitely need silent doors.
Rimworld Search Agency: Adds a search bar to many menus so when you're customizing a stockpile or outfit you can avoid a great deal of looking.
Allow Tool: So many great features, it creates the haul urgently labor which is a higher priority than general hauling and only applies to items you've designated- that way if you want to get some expensive goods out of the rain you can make sure that your pawns don't save them for last. Also adds the "Finish off" labor which is basically cutting the throats of downed enemies, it prevents that awkward situation where a mercy kill takes three hours and fifty bullets.
Fluffy Breakdowns: Reworks component failure. There's normally a random chance for any item with a component to break down any given day, so big bases devour components that can be a pain in the ass to keep stocked. Fluffy Breakdowns makes it so that items with components have a Maintenance stat that falls with time and grows when pawns work on them. Pawns work more often but losing a component happens because you didn't manage your colony well not because your prayers to the RNG didn't pan out.
Custom Death Randomness: When a pawn goes down there's a chance they'll instantly die, with Custom Death Randomness you can choose how likely that is.
More planning: Plan in ten different colors, tweak the transparency of your plans or set them to invisible, remove different colors individually- it all comes together to make planning out a base BEFORE you start building that much easier.
Blueprints: Do you have a building design that you really like or at least plan to use again? Save the blueprint and paste it wherever you want. You can export a design with two clicks and then import into any game with two more. I have a whole list of 7x7 and 13x13 rooms that I just plug in on a grid- it lets me spend less time obsessing over design.
Prison Labor: As the name implies your pawns can force prisoner to performing labors, if you combine it with Quarry it's a qood way to turn a drain on your food reserves into a net benefit without resorting to slavery or well,western apparel.
Set up camp: When in caravan mode you can "Set up camp" creating a tiny map where you can do anything you normally would. Not only is it fun you can do quite a lot with it, for example you can send out groups to hunt, collect wood, or do some mining then pull up stakes and bring the resources back.
Change Dresser: Store infinite clothes inside of the dresser, let pawns change their outfits from the dresser, even automatically donning certain outfits when drafted.
Weapon storage: Same basic thing but for weapons.
I could go on all day, there's a lot of good stuff out there.