Hi,
We cannot create a custom Table Style in the built-in list.
There might be two workarounds:
1. Create a template which includes the custom tables in a silde as sample tables.
2. Achive the above steps by using code:
http://msdn.microsoft.com/en-us/library/office/hh273476(v=office.14).aspx
Best regards,
Rex Zhang
TechNet Community Support
