I'm a student approaching my bachelor's degree with game design. For an assignment we're developing a proof of concept approached through our chosen specialization, and the specialization I've chosen is as an environment concept artist.

The question I have is, what kinds of tools/programs do concept artists need to know to be successful? Right now I'm only comfortably-familiar with various free art programs and social media. How important is it for professional artists to be adept with Photoshop, and what other tools are as popular/important? I've also started posting my art on Artstation, and am wondering whether to rely on that for my professional portfolio in the future.