If you want a few more accessories, you can get kits with a backpack or a cooler case. (expressing-mama.com)
T - 3 currently has a few more accessories available, though that gap is closing rapidly because Titan has been adding new X-3 accessories monthly if not more frequently as of writing this (Nov. 2017). (kingofthegym.com)
Frankly, once you really get into Grand Slam Tennis, you're likely to invest in a few more accessories to take advantage of the local multiplayer options. (cheatcc.com)