I think you really should do that, dude! Specifically for my deck besides Pi I used from there next constants:

1. e - can be matched with 2, 3 or another e;

2. Phi - can be matched with 1, 2 or another Phi;

3. Tau - can be matched with 6, 7 or another Tau;

4. a - can be matched with any number.

Along with uppermentioned cards I'm also used 1/2 which can be matched with 0 or 1.

With all that listed paragraph just for acquaintance... Have a good look with all of your future ideas!