[AdamProut]

  - Firebolt (Hard fork of clickhouse)
  - Altinity
  - Gigapipe
  - Hydrolix
  - Bytehouse.cloud
  - https://clickhouse.com/ ("coming soon")
  - TiDB (Their columnstore is a fork of clickhouse)

I stopped tracking after this. I saw a few press releases go by announcing a few others as well which I lost now.

The official Clickhouse Inc. is surely going to be under pressure to pull features out of their open source offering over time to differentiate themselves.