Gimp has generally been getting better and more capable for free, and hasn't launched any cloud-based subscription services, feature gates, ad-funded functionality or done price hikes like almost every one of its commercial competitors.

There's also Krita, which artists love.

That this comment keeps oscillating between upvoted and downvoted (with significant spikes in both directions) is an interesting insight into the span of opinions on HN between the hustler types who hate the idea of software that doesn't turn a quick buck, and the crafters :-)