Clip Studio Paint and Affinity are also well-regarded, though not FOSS. CSP in particular has great support and advanced tools like posable maquettes and perspective rulers.
While we (Krita) don't have 3D support yet, but we do have perspective and other kinds of rulers (assistants) support. There are lots of other features too like wrap around mode for seamless tile creation etc.
For the record, I have all 3 installed. :) I find that they're useful for different purposes and that it's helpful to be able to tap into two feature sets and support communities.