Update: 1.16 will be a full rewrite, including new models/textures and a change of License to MIT for code, CC-BY-SA-NC for art,

Have a few more:
http://greyminecraftcoder.blogspot.com/2020/05/minecraft-by-example.html
https://gist.github.com/williewillus/30d7e3f775fe93c503bddf054ef3f93e (1.15 primer)
MinecraftForge/MinecraftForge#5564 (ExtendedBlockState rendering)