There are only 4 of them and they are called Drives, not Cassettes.
- Burn Drive - Black only - Fire
- Douse Drive - White only - Water
- Chill Drive - White only - Ice
- Shock Drive - Black only - Electric
So the Douse Drive is the best. It is the best Water move Genesect can learn, but it is not the best Fire/Ice/Electric move it can learn because Flamethrower, Ice Beam and Thunderbolt are more powerful than Techno Blast (only 85 base power compared to 95).