I couldn't find any hint if it is possible to search for questions I voted on.
The only workaround I can think of is to add all those questions to my favorites but I'd like to distinguish between those I generally consider being good questions and those I find particulary usefull (mostly because of the answers to those questions).
Since this question keeps getting upvotes (and duplicates pointing to it) I'll turn it into a feature-request.
Since the discussion on social media sharing icons cropped up I figured that sharing questions and answers would be the most flexible way to have categorized bookmarks ("Non-Freehand-circle answers I downvoted").
I'd drop this request if I could share anything without copy/pasting from the link box.