There is now a plugin available to find questions in the question bank by searching the text. For example, you could find all of the questions (and answers) that contain the word "chocolate". This works in the Question Bank interface and in the quiz editing interface where you select questions to add.
Also visible in the screenshot i an upcoming plugin to find questions that haven't been used in a quiz yet, which can be useful for finding questions to add to a quiz - no need to look at ones you've already added. That plugin will be headed to the directory later when I get time to clean up the coding style (whitepace, etc.), write a README file, etc. Also coming soon is a plugin to find questions by Tags. That's also working, but needs style cleanup, a readme, etc. Volunteers accepted for that polishing work.