Quirky's Minecraft Wishlist is what I do when I decide there's something in vanilla minecraft that's missing, or that everyone is implementing in ways that I don't like. At this point it has grown into a very extensive collection of datapacks that can change the way the game is played in some unexpected ways.
My favorite might be headpats, that allows players to have a positive physical interaction with other players (or any mob, really) in a supposedly social game where the only way to touch something is to punch them.
The full code is in my gitlab.