As to the original question...
Good advice from those that have learned to keep it simple for prep and learn how to use the prep line you're on vs jumping from one to the other and never learning. After learning prepping isn't so difficult (takes time), you won't have so many different chemicals. But, you will learn how to mix the chemicals you do have specific to the current track situation. For example, here's what I always had in the trailer to mix/use as needed (and I mixed them many different ways and amounts to match the track):
Southern Comfort Pink (Inside)
Southern Comfort Purple (Weekly/Base)
Southern Comfort Bite in a Can (Primary PRW chemical)
Acrysol
Track Tac Blue Tire Wash
FTS Black Bite
Goat (Pure - not cut)
Velocity Tire Potion Mean Green (My choice for green prep)
NOTE: Southern Comfort Bite in a Can is akin to Track Tac Black Sand. Bite in a Can is mixed with Acrysol and/or a base like Black Sand but is stronger and doesn't require nearly as many wipes as Black Sand to create the bite needed.
Hope this helps anyone new to the prep game as to types and number of preps needed for most situations. The preps I listed were used on Maxxis and Burris (and any other tire I ran occasionally). Over many years of racing I did on rare occasions have a need to add Creosote, Methanol, and WD-40 to the list of chemicals/preps needed.