Ask HN: What external support do startups need most?

We're working on our first vertical dubbed "Startup Superstore" at www.work.io and would love to have your input. What makes you think "Damn, it would be great to briefly have someone who's great at X at hand"?

Could be code reviews by a core committer of the framework you're using, lists of journalists that are into the stuff you're doing, making sense of / cleaning up metrics, coaching sessions, SEO, legal etc.