1. Writing a built-in Tendermint Core application in Go (assigned to @melekes)
2. Writing a Tendermint Core application in Go (assigned to @melekes)
3. Writing a Tendermint Core application in Javascript
4. Writing a Tendermint Core application in Java (@climber73)
5. Writing a Tendermint Core application in Rust
6. Writing a Tendermint Core application in C++
7. Writing a Tendermint Core application in Kotlin (@climber73)

External contributions are welcome 🏆 Please leave a comment if you want to write a specific guide for X language. When ready for review, send a PR to master branch.

FAQ:

1. Does it have to be a specific application?
   No, any application will do.
2. Do I have to follow some structure?
   Yes, see the first guide in the series https://github.com/tendermint/tendermint/blob/master/docs/guides/go-built-in.md.

Refs #3016, #3169