which domain knowledge other than software engineering can help a tester generate good test ideas?
any books , courses, philosophy, theories , puzzles etc.
Research and Analyze. Period
I think these two tools are enough for a tester to generate creative ideas. And I would like to give you a simple example.
Talking of your question, if you would have researched the SQA website well enough, you'd have known that the question put forward by you have been asked multiple times- here and here. If you would have used the power of search engine and used these, you probably wouldn't have asked these questions at the first place.
Secondly, analyse the various points, links, videos put forward in the above links and I am sure you will benefit out of it.
Note : My answer is in no way bashing you.