I’ve talked about Star Trek Phase II and the unused Federation pitch before, but there are more Treks untaken beyond those. Looking this up, I found there was at least one I hadn’t even heard of, to make a CG animated movie about Enterprise B fighting the Kzinti. The fact that there isn’t a CG animated Star Trek spinoff feels quite odd, actually - there have been a number of attempts, most notably Final Frontier, which I discovered after my own attempt to come up with a “generation after next” setting.
As well as providing looks behind the scenes, many of these have easily borrowed adventure hooks.
Which ones would you like to see?