When research subject is not selected, pawns just choose the cheapest one on their own. This option is accessible from research bench.

Forgot to pick a new research?
Just want to go with a flow?
Ran out of care for what's going to be researched next?
Yeah, that's a mod for that. No gimmicks, just plain auto-select of a cheapest thing in the list.

External links: github[github.com]