Although I can't point to a specific application that's currently using TimescaleDB for an event sourcing service (I assume you're talking about the design pattern), it would be a great use case. Change in state over time is perfect time-series scenario.

As for SQLAlchemy, TimescaleDB is fully PostgreSQL compliant, so it will work out of the box. There will be a few nuances that need to be considered, particularly when writing queries that use some of our additional time-series functions like time_bucket.

But day-to-day ORM CRUD patterns should work as you expect!