> what kind of database drivers can I use in conjunction with this?

Usually synchronous database drivers have to be reimplemented in an asynchronous fashion to work with event loops. It's not very hard though, could be as simple as adding jump tables and context structures into synchronous functions.

Emulating asynchronous execution with a thread is ok too. You do that to access filesystem anyway.

But if your first thought is about accessing a database server - you probably don't need to go asynchronous at all.