Also interested by a way to test a lot of LUTs easily. When you have several set of LUTs it's a real pain to find the good one.
For my pack of LUTs I built an online LUTs previewer to test all the looks quickly. You have just to drop a JPG/PNG frame and then you can switch between LUTs with up and down keyboard arrow keys. It's extremely fast, once full web app loaded (around 10MB). Give it a try : preview.iwltbap.com
I started to build a standalone application that can do the same for external LUTs, but I had some issues and I temporarily suspended the project. It's complicated because, to be loaded in a second, each LUT must be converted in a specific format and for the moment I'm unable to automate this long multiple steps process. Even if it was automated it would take around 3-4sec per LUT. So if you have a huge library of hundreds of LUTs it would be too long. I don't abandon the idea but I'd be happy to find an existing tool to do this