[xigoi]

What are other choices for FOSS serverless relational databases? I’ve been looking everywhere and couldn’t find anything.

[homebrewer]

Firebird can be embedded, although neither the database itself, nor the embedded mode are as popular as they once were.

It's a fully featured database though, with everything you expect from one, including actually working ALTER TABLEs.

[lenkite]

DuckDB ? Strict by default and excellent for logs, telemetry, dashboard apps, etc.

[xigoi]

From what I can tell, DuckDB is more focused on huge-scale data analysis than simple data persistence, so I’m not sure if it fits my use cases. Otherwise, it looks good.