pg_mooncake (now effectively abandoned due to being acquired by Databricks, but still up at https://github.com/Mooncake-Labs/pg_mooncake) pulled the DuckDB engine into Postgres wholesale, if I remember right.

pg_lake also uses DuckDB but keeps it external, routing through Postgres and managing Iceberg tables (but not the data itself) there (https://github.com/Snowflake-Labs/pg_lake).

Both of these were neck and neck with ClickHouse last time I tried them.