I had tried doing a game startup together with another guy, but so far we rather failed selling our first (and only) game. But afterwards I learned about another business models rather accidentally - advertisment for myself. We kept our website up and just having finished a good looking game was enough to get people interested in working with me. I do now freelance work and that game is my main selling point.
Also missing in the list was that you can certainly also sometimes sell the technology of your game.
Also missing in the list was that you can certainly also sometimes sell the technology of your game.