Wizard is the company that spawned the style of skating called wizard skating. It is owned by Leon Basin, who is also the owner of the inline skate retailer Shop Task. The Wizard shop mainly just sells their wizard frames, which are produced and designed by them. The other things in the shop are just top-quality liners, boots, wheels and bearings from other companies such as Intuition and Seba that you can find elsewhere. Their products are incredibly expensive, which is quite understandable given that all of their products are premium and of top quality. Overall, unless you want the best of the best and want to burn a huge hole in your pocket, you should be buying from somewhere else. And yes, that includes their proprietary frames as well.
Like Wizard, Endless is a company that specialises in frames, specifically wizard frames. Endless frames are far cheaper than their wizard counterparts, though their frames are different from the original wizard frames. However, they're far cheaper than wizard frames which makes wizard skating more accessible to a much larger group of skaters. Their frames are about half the price of regular wizard frames, which means you can try out wizard skating at an affordable price. Similar to Wizard, the other products in the Endless shop are mostly just products from other brands, except for the Endless wheels. If you're looking to give wizard skating a go, you would do well to pick up an Endless frame.
Kizer is a sub-brand of Powerslide that specialises in frames, mostly aggressive skate frames, but they do sell a few freestyle and wizard frames. Their frames are pretty affordable, especially when compared to the other frames out there. If you want to change the frames on your aggressive skates or try out wizard skating, you should see if Kizer can meet your needs before going to other brands.