https://osgameclones.com/ is the best aggregate for this kind of thing.
https://libregamewiki.org/ also looks like something relevant.
Maybe now that we have a messy thread of various links, we can go check whether some of them are not yet listed in osgameclones.
There is a project called Example Suite, which is meant to be a CC0 template for building other games upon it.
But I am not aware of any other from-scratch games made for OpenMW. There are quite a few total conversions, but those all use some of Morrowind game files.