Intentionally or not, the best way to keep villagers is locked up in isolation chambers in a big, less-than-OSHA certified trading hall, forever locked in place and periodically attacked by zombies as an endless source of cheap labor. Not only is it the most efficent method, but villagers are such a valuable source of resources that villager-cruelty isn't just condoned, it's incentivized. If you too have grown TIRED of this mindless cruelty, this sideproject may be for you.

Villager Tweaks doesn't nerf villagers, but rather disincentivizes the trading hall setup in favor of a more natural, (humane) sort of village that feels a bit less exploitative. Villagers have various desires that need to be met to keep them happy: unhappy villagers refuse to trade, but happy villagers grant occasional gifts to their benefactor. Specifically:

Villagers like decoration. Decorating their surroundings with candles, bookshelves, paintings, pottery, flowers, and other decorative blocks will improve their mood.
They enjoy good health, and become crabbier when injured.
They need to stay hydrated, and become cranky if there isn't a source of drinking water nearby.
They want to be protected by golems, and can become frightened when attacked by players or monsters.
They enjoy friends, and are happier with other villagers around. Don't overcrowd them though, or they'll start to get overwhelmed.
And of course, they need some space to move around. Lock up a villager in one place and they'll eventually get mad at you.

In addition, the mod adds a Deed Box; a block that can summon a villager, and binds itself to the first villager it encounters, giving information on their state, and allowing the player to call them back to the box, or dismiss them from the village. (In a non-murderous fashion.) Effectively providing a less janky means of creating your own village, which does not require kidnapping. Even better, if you're nice to your villagers, they might leave some handy gifts inside...

This mod is still in development, and may contain bugs. (Nothing game breaking, at least from my playtesting.)

The Deed Box

To make your own village, you'll first need to craft a Deed Box from copper, redstone, tinted glass, and an emerald block. The recipe is unlocked when you obtain emeralds for the first time. This special block is used to summon villagers, interact with them, and accept gifts. It won't drop when mined, so place it wisely!
After 10 minutes or so, the Deed Box will attempt to summon a villager nearby. (This can be configured with the villagerSummoning gamerule.) The villager has a 50% chance to be of the local biome type, and a 50% chance to hail from a random biome, granting you a chance to encounter rarer villager types, such as Swamp and Jungle villagers!
When a villager is near a Deed Box, (summoned or otherwise), it becomes bound to that box. A Deed box will become adorned with emeralds to indicate it's already bound to a villager. You can then open the box's inventory to examine the villager's stats, order the villager to return to the box's location, or dismiss them from the village.
Keep your villagers happy, and they might drop off gifts in their deed box!

Decorating a Village

One way to improve the mood of your villagers is through tasteful decor. Use a combination of candles, flowers or flowerpots, bookshelves, and other decorative blocks like pottery and lanterns to further improve their mood. Paintings will also grant some additional favor to nearby villagers.

...But don't go overboard; as much as you'd like to build a house out of flowerpots, villager's won't notice more than ten decorative blocks nearby.
The flowerpot icon in a villager's trading menu shows their current satisfaction with their surroundings. You can also check their deed box for more details.

Helping the Villagers

But it'll take more than tasteful decor to keep your villagers pleased. Villagers have several other things that determine their mood. Happy villagers give gifts more frequently; but if villagers get angry enough, they'll refuse to trade with you.

Villagers need to be healthy to work- a villager at full health has a better mood, but feels worse if they lose HP. A seriously injured villager won't be able to trade. You can check the heart icon in their UI, or in the deed box, to determine a villager's health.
Villagers need access to drinking water, from a water source, cauldron, or waterlogged block. If a villager hasn't found water in more than 15 minutes, it decreases their mood. The water bucket icon in their UI indicates their current hydration.
Villagers need to feel secure. If there's monsters nearby, or if they're attacked, they'll be temporarily frightened, decreasing their mood. If they're extremely frightened, they become terrified, and unable to trade. A villager who isn't currently frightened, and has recently seen an iron golem, has a better mood. This is indicated by the skull icon in their UI.
Villagers need friends, unlike yourself, ideally more than 5, less than 12. If a villager hasn't seen any other villagers in awhile, they'll start to get lonely and despondent. Conversely, if they're overcrowded, they'll get increasingly cranky. Try to house your villagers accordingly. The little sun icon in their UI indicates the current state of their social lives.
Villagers need sleep, unlike myself. When a villager is out of bed during the nighttime, they slowly become tired. An exhausted villager is unable to trade, and can only remove this effect by sleeping in a bed.
And lastly, villagers need mobility, indicated by the boot icon in their UI, which is determined by the furthest point they travel from wherever they woke up. A villager who's walked at least 32m in one day gets a mood boost. If a villager hasn't traveled more than 18m from their bed, their mood decreases significantly. This always updates at the end of the day.

Villager Gifts

A happy villager can drop off gifts in their deposit box. The happier the villager is, the more frequently they're able to give gifts. When a deed box has a gift in it, its interface will change, and its brightness will increase. You'll also get an advancement for successfully enticing a villager to give you something.

Each gift has a 5% chance of being an enchanted book, which can include treasure enchantments.
They then have a 10% chance of being an enchanted tool or armor piece, including horse armor, saddles, and the like.
And an 85% chance of granting other items, including baked goods, metal ingots, emeralds, and even an occasional diamond, in order of usefulness.
...Which makes happy villagers a slow, (but renewable) source of certain valuable items...

Angry Villagers

When a villager becomes malcontent, they will refuse to trade with you. There are a couple of reasons this can happen, detailed further in the UI itself:

If the villager is too wounded to trade, (in which case they simply need to be healed).
If the villager is too tired to trade, (in which case they simply need to get a good night's sleep).
If you have a Mark of Suspicion. This effect is inflicted on a player who attacks a villager, or is in the vicinity when a villager dies. Hero of the Village removes it, but milk does not.
If you have a Mark of Terror. This effect is inflicted on a player who has killed a villager. It takes longer to expire, and cannot be removed with milk or Hero of the Village.
If the villager is too upset to trade. This means at least two of their needs aren't being met. Consulting their Deed Box will give advice for improving their mood.

Lastly, Villagers are further granted custom names by this mod pack, to better distinguish them. (As well as randomized skin tones and other facial features, with optifine installed. THESE ARE DESIGNED FOR 'FRESH ANIMATIONS,' and will look weird if you don't have said resource pack installed.) If ya wanna know more about the naming process, see the tab below.

There are 280 custom names that can be granted to a newly spawned villager; 140 sort-of masculine, 140 more-or-less feminine; 32 names are rare easter-eggs selected by myself, 48 are just random, less common names I thought sounded nice, and the remaining 200 are taken directly from the Social Security website's list of 100 most popular names in the U.S, 1943-2024. To be honest, I couldn't think of a way to do this that wouldn't be in some way exclusionary, so I figured I'd pin the blame on someone else's statistics.

That being said, if you want villagers with common names for your own region, I'm happy to add some more localizations to the mod!

This project's source code is now available on Github. Use it as you wish.