There are IR's on the axe fractal page that are really interesting. There is a bundle with 5 packs for 9,95 dollar. It's a steal. See https://shop.fractalaudio.com/…roduced-by-fas-1-2-4-5-6/. These are SYX files. The Kemper cannot read them. But they can be converted. Searching for a conversion I found several interesting options on the net.
I found a converter converted ans converted them to wave files on a Mac with Axe-o-matic. See: http://archive.axefx.fr/Tools/old/. (windows files too). It works with the shorter files in the first two packs. I'll have to check out the longer files.
I've read that the conversion is not the same as the original file. I cannot control that but to me the converted wav files sound convincing. There are lots of Vintage Cab/Amp ir's in the packs. I've bought several Redwirez, Ownhammer and Cabir packs but these converted files are usable and (at my opinion) good sounding too.
You also can get the first two packs with lots of interesting amps of this bundel for free. They contain the shorter files.
Free IR s from Dweezil Zappa too, in honour of Frank Zappa's 80th birthday