Promotion (as in pro-motion) is well respected indeed for painting and also animation in creating game art. It has numerous formats for various game engines, if I recall. Many of the keyboard shortcuts are the same as in Project DOgwaffle, because both Dogwaffle and Promotion are heavily inspired by a common predecessor, called D-Paint (DeluxePaint) that was a very popular paint app on AmigaOS 20 years ago. For example, in both applications the 'j' shortcut is used to 'jump' to the alternate image buffer (also known as the swap buffer).

For painting without animation there's also Pixarra's Twistedbrush. It's around $79

Pixarra is also one of the very few which have particle brushes with presets for shrubbery a bit like PD Particles (a $19 proggy derived from PD Pro and focusing on the particle brush system).