At the top of my list would be
mouser, who has been both immensely helpful and immensely patient!
Here are some others, listed alphbetically:
HyperSnap - I haven't had many problems with this excellent screen capture program, but when I have, the developer and the forum have been responsive and helpful.
Linkman - An immensely useful bookmark program, with extraordinarily fast and helpful support.
Malwarebytes Anti-Malware - Available in both free and "premium" versions. I use the latter. Whenever I have questions, I've received fast and helpful responses from both forum volunteers and paid staff.
Pale Moon - My browser of choice for the past four years, partly because the changes it makes seem more sensible than those of Firefox, and partly because the PM forum offers consistently informed and helpful responses, including many from the Pale Moon developer, who apparently never sleeps.
Pimlical - Not sure whether I should include this, since it's primarily calendar software for smartphones and tablets, but it's also available for Windows, Mac, and Linux. The calendar is exceptionally feature-rich, which means it's also rather complex. Fortunately, there's an excellent forum and a responsive developer.
SoftMaker Office - a very capable alternative to Microsoft Office at a fraction of the price (and I think there's also a free version). Anytime I've had questions, responses on the forum have been prompt, informed, and helpful, from both ordinary users and staff members.
