"Photopea. It's a Photoshop clone that is completely free (unintrusive side banner ad, can be removed by a one time payment) and has all the basic features of Photoshop, using basically the same interface. If you're used to Photoshop and just need to get something quick done, there's nothing better out there. Best of all, it's completely contained within your browser. There's no installation, no local files, not even an account or sign in."