Partly inspired by this question
My Venusians are happy in their cloud top city when a small group somehow (with lots of handwaving) crashes to the surface, falls underground, and ends up in a hidden cavern. Our Venusians are in some sort of vehicle that can survive the local conditions, and like caves on earth the conditions in this underground cavern are similar to those above ground. To everyone's surprise they find life living in "pools" in the cavern.
I'm going with pools because (duh!) everyone likes/expects there to be underground lakes/rivers. Also I generally expect liquids to be a requirement for life anyway, as their ability to dissolve other chemicals and act as a medium to speed up chemical reactions is very important for all earth life.
Obviously though these "pools" are not composed of liquid water. Earth gets water lakes, Titan gets methane lakes, but what does Venus get? Given what we know of Venus, are there any plausible candidates for chemicals that would be liquid at VSTP (Venus Standard Temperature and Pressure) and might actually be around in enough quantities to form pools?
There is already a lot of handwaving going on, so if need be I'm happy to loosen the "present in sufficient quantities" requirement.