Here is a list of RPO codes. The letter or number represent what the option code begins with.It's by far not complete. If you have some that I don't, email me at rand007@athenet.net.

0-1-2-3-4-5-6-7-8-9-A-B-C-D-E-F-G-H-I-J-K-L-M-N-O-P-Q-R-S-T-U-V-W-X-Y-Z