An index for trope pages whose images are panels from XKCD comics.
I've noticed that a great many pages have frames from XKCD for images. I began compiling a list on Trivia.XKCD, but if I make it its own page I can turn it into an index. Tropes Examined By The Mythbusters is an index, so why not this? Every entry on the list is accompanied by a link to the comic or comics the image comes from. If you spy a panel but don't know which comic it's from, the webcomic has a transcript search feature for easy finding.