There's an old, famous/notorious, surly beast of a mod called Better Than Wolves. Its creator offers it as a sharp criticism of the direction Minecraft development took, and as a vision of what he sees as better content (hence the title). A lot of vanilla mechanics are altered, and the early-game especially is more challenging. While the mod has a lot of cool ideas and interesting mechanics, it's incompatible with the majority of mods for Minecraft and has been kept on a version of the game from 2012. Better Than Mods is a "re-imagining" of the original's content that is designed with a mind for compatibility, and updated to the latest game versions. I'm excited to try it out- I steered clear of the original mod for, ah, various reasons.
This rather charming mod adds some more low-tech and agrarian content to the game. New crops and building materials, an alcohol brewing system, pottery, and more. It reminds me of an older mod, Growthcraft, which I love.
Minecraft Comes Alive makes the boring, ugly flesh-Squidward villagers into something more resembling actual people. Aside from giving them a nose job and a face lift, villagers now have moods, personalities, and relationships between each other and with the player. You can chat with villagers, exchange gifts- even potentially marry a villager and raise a family. Even if you're not into the latter, I think the mod does much to make villagers more interesting and developed- more than empty shells to be bartered with (or stuffed into horrifying contraptions to be bred and slaughtered en masse).
These tents are a great help for the explorer. The inside of a tent is a dimension unto itself, so that you can have a safe place to rest your head at night. But I feel it's "balanced" in a good and mechanically interesting way- after placing your tent, you have to erect it by whacking the various blocks with a mallet. This means the tents aren't just an instant escape-you still have to be careful and have a plan to set up camp as night falls.
EDIT: Unfortunately, on further inspection, this is not yet available for 1.12. My mistake!
I love the themeing of this mod, and the way it implements magic seems interesting and unique. In the Great War of Magic and Tech Mods, one sometimes hears the critique that magic mods are merely tech mods with a different skin. So mods like this that present a more mysterious, even spiritual approach are exciting.
There are a lot more mods that I'm interested in trying out for 1.12, and others that I sigh wistfully at and hope they soon will be updated. But hopefully you can get a sense of the pack I'm working towards here- an experience not so focused on technological marvels, or world-shattering arcane power, or an intense RPG experience. Something more down-to-earth, more focused on the early game- the part of the game I most enjoy, when you're doing things by hand and "survival" is actually a meaningful struggle. Maybe in a fit of uncharacteristic un-laziness I'll put the pack up somewhere to share it- but I wouldn't hold my breath if I were you.