For space opera, look no further among my works than the Peltedverse. This setting deals with the social implications of genetic engineering, the culture clashes between aliens, the frictions that lead to interstellar wars and of course, space elves and their royalty. The sprawling Pelted universe has been in continuous development since the early 1990s and it shows in the depth and breadth of the material. Constructed languages, artificial cultures, multiple alien species working together in harmony (or not)… if you want big, friendly universes full of growing pains, this is your stop.
The Peltedverse is so big there are three distinct branches: the general stories involve the Pelted and their relationship with humanity, which engineered them; the military stories involve the Pelted’s quasi-military as it struggles to re-invent itself as something effective despite its conflicting missions; and the Eldritch stories involve the reclusive “space elves” of the setting and tend toward the romantic.
More information about the Pelted can be found on the Peltedverse wiki, including a List of Stories in their Chronological Order, as well as by Date of Publication.