I only managed to visit a few talks during the GDS 2017. We had a desk in the Indie Expo section with our game WesTurn and that was a bit busy. Nevertheless, here are my notes from one of the presentations.
This is a really good talk about putting your game on Steam. What I like about it is making you think about marketing of your game instead of telling you what to do.
PixelProspector offers a great guide on gamedev marketing
List of various youtubers