Ok! So many/most want bass for testing! Bass comes in many flavours from going deep to going plenty. Some songs by artists not associated with bass but have satisfying amounts of it like "King of the Mountain" by Kate Bush. For the 'thinking' basshead, "Mixed by Fear" by Front 242 is very well recorded with plenty of top end as well that lesser speakers or systems will either smooth over or tear your ears off over. For shear doom-laden amounts, most stuff by 'Quantic Spectroscopy' will remind you of the end of civilisation. Liking any of it is another matter, of course. If you want your bass tight & low, try "Roast Fish and Cornbread" by Lee Perry may have yoy grinning. The other aspect regarding bass is how tolerent you are to hitting room resonanaces - I prefer my bass to sound realistic & not effect mid-range clarity so I have my speakers & seating away from walls.
If you care about the rest of the audio spectrum, vocals to test mid-range clarity is a good start & the humble triangle from orchestral works will test the upper treble for realism, otherwise, its still the music one is familiar with!