Anyone have good links or articles for DB comparisons to get a better understanding of which DB fits best for what type of projects?

So far I've gathered from here is that I want Postgres if going for a SQL DB, MariaDB as a MySQL drop-in, Redis for a simple NoSQL cache DB, RethinkDB for real-time applications (if project is still ongoing), and then there's CouchDB, CockroachDB, Cassandra, etc. which I still need to look in to.