Create Mod by Simibubi is my all time favourite mod. I don't think i can play without it anymore. It has loads of amazing things you can do and it is very high quality mod with fantastic user interface. But the thing I love about it the most AND the feature I would love to be added to vanilla, is the ability to create and generate blocks and materials that are otherwise not renewable. Such as sand. So many blocks and items can be converted into others it makes survival mode feel a little less grindy.

The first thing to spring to mind is Evokers "wolololololo" priest chant from Age of Empires II changing sheep colours between red and blue. It always makes me want to play AoE2 again (and is why the remastered one never gets uninstalled).

The second, i think is just speculation. Since the Nether Update and the introduction of warped wood. When an enderman makes their non-agro noises it now sounds like "warped wood" not "whoop whoop" or whatever sound they're supposed to make 🤣