Affinity Photo (An Adobe Photoshop alternative) is now free to use*

If you're looking for an alternative to Adobe products, this is a great place to start if you don't mind it not being open-source. It also works great on Linux under Wine with no noticeable issues which is awesome.

*All the basic features are free to use, but if you're a user of Photoshop's generative fill, smart select, or other AI doohickeys and want to use those kinds of things in Affinity, you have to pay a small monthly subscription.