- pganalyze: https://pganalyze.com/

- Weekly series "5mins of Postgres": https://www.youtube.com/channel/UCDV_1Dz2Ixgl1nT_3DUZVFw

- How Postgres chooses which index to use: https://pganalyze.com/blog/how-postgres-chooses-index

- CMU databases courses: https://db.cs.cmu.edu/courses/

- Postgres community: https://www.postgresql.org/community/

As well as social links:

- Mastodon: https://hachyderm.io/@lukas

- Twitter/X: @pganalyze, @LukasFittl

- GitHub: @pganalyze, @lfittl

- LinkedIn: https://www.linkedin.com/in/lfittl/ , https://www.linkedin.com/company/pganalyze/