Hey! I was inspired by williewuss's primer to create a guide on what is changing in 1.16, from mostly a worldgen perspective. This guide is just an overview on what Mojang changed, not what Forge changed.
However, I know that not everyone makes worldgen mods so I'll also include a section on non-worldgen stuff.
For the Forge people, this guide uses Yarn names! You can find the conversion at the bottom.
If you have more info, feel free to contact me and I'll add it to this list.
Last updated: 6/6/2020, 1.16-pre2