Old tstat has the following wire codes some that aren't identified in wiring instructions:
Old wiring;
G
Y1
R
E
W1
O
C -states not to use

Also saw a pink and gray wire not labeled that was pushed back and not used on old tstat
Can anyone help?

This thread should help you understand the color coding better https://www.askmehelpdesk.com/heating-air-conditioning/heating-cooling-maintenance-repair-troubleshooting-frequently-asked-questions-58313.html#post268211