You should definitely put into the app description that it supports all the common puzzles. This is not really clear from the description and I was looking for a timer that supports at least 2x2, 3x3, 3x3 BLD, 4x4 and 3x3 OH. I almost didn't install it since the description is not clear about it. But I was happy to find out it does support them.
You don't have to provide an exhaustive list, but just mention that you DO support the most common puzzles.