Ask HN: Drop your favorite mentorship orgs

I've got a bunch of friends that are interested in starting their own enterprises but are having a hard time finding mentors. Right now the main sources of mentorship seem to be ondeck and y combinator, but these are for people who are interested in build tech stacks and apps - what if you want to start a spacetech company? or an online publishing company? or an online fitness co? All things that are going to integrate tech, but which don't actually fit into the ondeck/ycombinator model.

interested in seeing what you guys have come across..