There's a section on the robot wars wiki for robots that are still competing today, that'll be a headstart. Next, I'd go on the roaming robots website to add any robots not on the wiki. After that, I would ask around the forum or check the box next to people's names for any "[insert robot name here]HW". I wouldn't trust the forum section, though; it looks like it hasn't been updated in a long, long time. Hope this helps.