Ask HN: What tools do you use for product design/roadmap management?

Not so much a question about what you use to do mockups/ui design (although happy to hear of alternatives to balsamiq, invision, etc), but what tools you use to conceptualize and design the product and roadmap itself.

(Inspired by https://news.ycombinator.com/item?id=22827275 I was interested in what tools people use for this type of thing)