The Song Rhythm Tracks service currently supports about 60 different distinct rhythm categories, which includes about 250 distinct rhythm types. Most of these are available with differing instrumentations and many are recorded at multiple tempos. In all over 3,700 different rhythm options are available, each a separate recording. The app makes selection easy by filtering on a musical meter (say 4/4 or 3/4 time), and feel (even or straight, 8th or 16th notes).
For a full list of all rhythm categories and rhythm types available, see the page http://alive-drumming.org/catalog-rhythmic-styles/