Personally, 10GB. It's a database of all "person pages" on English Wikipedia with some extracted text (infobox and sections) compressed using sqlite-zstd[1]. About 350k rows.

(I know this is "small" compared to what SQLite can handle, but it's the biggest I've worked with. Most of my SQLite databases are under 500MB).

[1]: https://github.com/phiresky/sqlite-zstd

Currently 55GB, for read-only work at the moment. Using full text search, rtree, JSON, and indexes.