My black cat Foster used to play fetch ALL THE TIME when he was a kitten. He had two best toys for fetching:

(1) I wear "Cornsilk" brand face powder, and it comes with a round, white, furry powder puff. I prefer to use a sponge, so whenever I get new powder, the new puff goes to Foster. (There's probably a whole herd of 'em under the refrigerator by now, and believe me they don't stay white.) Anyway, Foster hadn't fetched in MONTHS, but I opened a new package of powder recently when he was nearby, and he started dancing around and chirping. Maybe the new-puff smell triggered his memory, but he wanted to fetch! So, I threw the puff across the room and, sure enough, he brought it back. He was only good for 3-4 times, though, as opposed to his kitten days, when he would fetch nonstop as long as someone would keep throwing. My dad once tried to outlast him and could not!

(2) The other best-fetching toy for Foster was a clear, plastic circle that came on a new pair of socks (to hold the two socks together). It is about 1.5" diameter, and has the added factor of being transparent, making it a little more challenging for him to find once he got across the room.

Word to the wise: Beware of fetching-related tragedies--once you throw that toy, wherever it lands is where the cat will go. So if that toy lands in the potted plant, and disaster occurs, it's your fault--not the cat's! (I'm not that great of a thrower, so we had a few incidents...)