Looking through the ideas on the verses could make my own for some crossovers, or original ones since I got some ideas of my own and maybe related to the main story setting for fanfic ideas. Some characters would be based on others or a little different to make them diverge from the canon franchises.
Some ideas perhaps like Independance Day aliens could be an ancient rival of some of the old races like the Combine when mentioned they fought in a long war agaisnst he Spheres or some like the Ascendancy, Combine or the Human Republic
more to add...
Characters[]
so working on characters and some ideas after reading much of the lores and stories, although getting use to the idea of characters that can live for thousands of years, I mean least some could die to leave a legacy and stuff. But some I could make as alternate versions of another or in moments between certain events.
for the Ascendancy, while making them a higher evolved form of the ancient humans, need to make some limits to their powers, some believe in their course for 'bringing order' to the universes and the new humanity, but some see them as a repeat of the previous cycle of destruction they suffered and believe themselves to be the inheritors if humanity.