Tennis is definitely the most popular. There are differences between all the racquet sports.
It uses closed paddles instead of stringed racquets.
The big difference of a Table Tennis paddle form a tennis racquet is it's size and composition. The table tennis paddle is small and made of red and black rubber while tennis racquet is long and made of slim steel and string.
it dose not use a ball
A tennis or other sports racquet sold at retail is technically "prestrung" (ready to use). Pre-strung means the racquet is shipped to the store already strung and that is the way you purchase it. In specialty sports stores and pro shops, you purchase the racquet, choose the strings, and have the racquet strung at the tension you request.
There are many sports like rugby, hockey, tennis, badminton, ice hockey.