Competitive research. Having your VA research these tasks & put together a database of information becomes a 1-day task that has immense value down the road.

Customer Service - haven't done this yet - but having them take messages, be my secretary, handle refunds & answer 80% of the support messages that come in (usually variants of the same problem with a fixed, simple solution).

Basic writing skills (non-native english is tough here, but if you want just a paragraph or so written, they can usually do a pretty good job here - after which I have an native-english editor / copywriter go back through & clean up any leftover artifacts).