Hard to tell which ones are the most interesting because most of them say they do AI/machine learning, but it turns out to be still a lot of manual work or just a marketing thing. The challenges with real AI/Machine learning are big and even at the biggest established companies they cannot really seem to crack it. Let alone a small team at a start-up. A project that could be a step in the right direction at the right point in time is maybe Gems.

I guess you can say the ideas are interesting but I have not found one project of which I think they will pull of what they say they will do.