As per your request, I am re-submitting my comment as an answer.
Visit StackExchange and click on "tagged questions". There, you can create a "tag set", i.e. a collection of questions with certain tags (or just all questions) from any site of the network. E.g., you can add all questions from StackOverflow, questions tagged "grammar" from English Language and Usage, questions tagged "bug" from Board and Card Games Meta, and so on. Asterisks can be used as wildcards, e.g. "gnome*", "*architecture", or "*crypt*".
You can create several different tag sets. You can also browse the tag sets created by other people and/or save them to your tag sets.