pg_max_connections
Keep its value under 1000 connections.
pg_effective_cache_size
75% of physical available memory to PostgreSQL.
pg_maintenance_work_mem
12% of physical available memory to PostgreSQL.
pg_max_wal_senders
Max replicas you expect to have, doubled.
pg_max_parallel_workers
Number of cores divided by 2.
pg_shared_buffers
25% of physical available memory to PostgreSQL.