Turning The Database Inside Out: Martin Kleppmann - https://www.confluent.io/blog/turning-the-database-inside-ou... in both video and blog form. Describes how to think about any software stack as layers of derived caches on top of immutable event logs, effectively proposing a solution to the first of https://martinfowler.com/bliki/TwoHardThings.html . It's certainly changed the way I approach software architecture.

Honorable mention: https://www.destroyallsoftware.com/talks/wat