Other databases (Postgres, MySQL, etc.) already have clients written in pure Go. SQLite does not have a client/server architecture, so a pure Go version of it requires porting (or transpiling) the entire engine to Go.

Etcd, CockroachDB, InfluxDB, Consul. There are more.

Also Bolt is pure go which is a highly performant KV store

I tested that for a while but it seemed to suffer lock contention with a lot of go routines trying to use one database at the same time.