Newbie here and didn't find anything on a search. Using expertflyer.com to view available classes. Attempting to find routing from DEN to FRA in June using Mileage Plus saver award. One option was available through YYC to FRA on Air Canada, but times didn't work out. Trying to do some legwork on my own without having to call United.
The codes I'm aware of are N for United economy awards, W for Air Canada, and X for Lufthansa. Is anyone aware of other booking classes that economy awards may be booked into? Below is an example of an LH flight that doesn't show X class at all.

Many thanks in advance.

Connections
LH 457 0 LAX
06/12/06 02:45PM FRA
06/13/06 10:20AM 747 M F9 A9 C9 D9 Z9 Y9 B9 M9 H9 Q9 V0 W0 S0