Email developers of applications or games you'd like to see on Android TV and ask when or if it'll will be supported soon. Let them know we're here and that there's market.
I've sent several out and got a typical "No plans at this time" mostly, but others thanked me for my feedback or said they're working on bringing their game to the Android TV platform.
I put my game on AndroidTV after just one user asked. Admittedly I had been considering it for a year, and it already had good controller support, but seeing just a single person actually want it added just the urgency needed to go through the rest of the process.
It's easy for devs to think no-one wants it ... when no-one is asking for it.