During the past two sessions recently, the guys I photographed brought some simple props that related to their sports interests. The result for both sessions was a more personalized and authentic image for each that was much more powerful.
A prop can be almost anything. One guy I shot plays piano and while he didn't bring a piano, he brought a music book featuring his favorite piece. We used the book in the image and it worked great.
Props can be very personal to you or fairly generic. I've photographed guys with a motorcycle, bicycle, viola, army tags, hats, all kinds of clothing, boots, leather, cock rings, flags, bondage toys, rope and chains, food, trumpet, animals (G rated), sports shirts, mesh shorts, etc.
What seemed critical for making great shots for the sports props is that the model instantly became very at ease posing in a manner that was second nature to them. One was a swimmer who easily did some strokes and the other was a kick boxer who provided some wonderful poses. These create more interesting images I believe.
Try to think of things you like to do or wear or somehow link to your life (could be related to your heritage or place you have lived). A prop can also be something that isn't really related to your life (such as a ball or US flag) and it can still add interest. I keep some props ready to go for all shoots.
If you're considering bringing a more intimate prop such as a sex toy, that is ok with me too. If you're comfortable posing with something, consider bringing it. For the motorcyle shot, I rent a larger studio where we can driver a truck in the studio if we wanted to do so.
In addition to physical props as described above, I have also used water or food to create interesting images. Be creative and keep an open mind!