LiteDB
A pure C# embedded NoSQL database with BSON documents, queries, indexes, transactions, and encrypted files.
Why use it
It stores player profiles, editor projects, and complex local caches without an external service.
Where it fits
Find engines, frameworks, code libraries, version control, and production automation.
What to check
It is not an authoritative multiplayer database; test write concurrency, AOT compatibility, and long-term schema migrations.