Crossover Spectrum is a pad pack series started by Dossar (myself) that specifically focuses on crossover patterns in certain BPM ranges. Listed below are some of the benefits I aimed to give with this series:
Currently the series covers ranges 100-225 BPM in 16th notes, with Part III being the most recent release. Only Singles Charts are available for now; a small doubles expansion for Part I is in the works and will feature new songs. This series is continuous and eventually it's planned to also have double charts for the original singles releases.
Every Song in the pack series has three difficulties: Medium, Hard, and Challenge. Any other chart difficulties provided that aren't a part of those three are not part of the specfication. Some files might have an easy chart with arbitrary non-crossover stream, and there is a case of a song with a Beginner chart (CROSSOVER CHART from Part III).
If you've looked around the site already, you may have noticed that the packs have letters assigned to them. The I's represent the BPM range that the pack covers, and then any future expansion to that BPM range is covered by a letter different than I (starting at A).