Do you want something SUPER custom and kinda obscure? Then Etsy either already has it, or the Alchemy part of the site will help you get it created for you! Just realize however, that a lot of this stuff is NOT cheap.
This is the key to learning how to catch almost all of your programming syntax errors. LEARN TO CODE IN NOTEPAD! Once you master the use of a simple word processor, you will always see that missing semicolon or parentheses.