In addition to Postgres FDWs, Steampipe plugins are also available as a SQLite extension [1] or a CLI export tool [2] for lighter weight use cases. (Although a local Postgres has a surprisingly small footprint!) Building plugins as DuckDB extensions would be cool too, but we haven't done that yet.
1 - https://steampipe.io/blog/2023-12-sqlite-extensions 2 - https://steampipe.io/blog/2023-12-steampipe-export