I need a spellbook manager. Or some other tool, not really important for the sake of discussion. Can I ask about it on main site? Or would it be off topic? I know software recommendations site, but I doubt that many RPG players will able to see what I ask there.
Sure! Take a look at the tools and online-resources tags to see the kind of questions that have been asked already. Your question might have been asked and answered already, and if not you'll get a sense of the detail questions need to have in order to get good Stack Exchange answers. As always: describe the problem you're facing more than the solution you expect, giving more specific detail rather than generalising the question in hopes it'll be more useful to others.