Trying to create a list of priority tools to learn in Houdini and want to prioritize tools that I'm most likely to get paid for in a freelance situation. I haven't done freelance as a Houdini artist (I'm also c4d guy) so I'm curious what others experience is? What do you get called upon to use most often professionally?

I’m not sure how to answer that. Features are dependant on what work you’re doing and which areas you want to focus on. E.g. procedural modeling? look dev? VFX? CFX?