#3,4 and 5 are called High Lifts..They come on most new mowers..They provide the most vacume out of all the blades..
The Gators are just a different kind of mulching blade..Most guys put these on during the fall to help mulch up all the leaves..I dont like them because they tend to leave alot of clumps..
The last blade is a medium lift blade..
The wavey blades in the first post are used when you have a recycle kit on your mower.. I use these the most..They cut great and are quieter then most blades..
Hope this helped.