Agree. Just like any other famous sports, table tennis should deserve its own stamp. As prvosenka mentioned, table tennis is considerably popular across many countries and ocuppies a noticeable place in the ranking of popularity, and that strongly supports the idea of creating a stamp for the sport.

Although similar to tennis, table tennis is a unique sport and has its own techniques and gameplay, it is in fact an Olympic sport.

Something that has not been discussed is how the stamp should look like. Although it might be straightforward, I suggest that it contains one player striking a white or orange ball across a table (typically blue), and some details indicating movement while the player hits the ball with their racket.

Here are some references for the stamp: