I know about Qualifeye, but there's not a lot on there. Is there a more complete list available anywhere?
I don't think a master list exists because for the most part, qualification tests are not static for various reasons (e.g. not always posted by the requesters, time sensitive, enough workers already, etc...). Even for some of the less desirable, underpaying HITs, I don't think a list exists. QualifEye scrapes constantly to find tests that are currently active. It seems to keep around 6-7 days worth, then older tests fall off the list. Your best bet is to check periodically and knock out all of the qualifications that you can, or care to work on.