The only things that I've found to be meaningful for myself were:
- Helping US win their last GST
- Full-year Mixed sweep
- Getting a Mixed/iDevice win in the same season with Alumni
- Helping both the Mixed and iDevice players with the most respective GST wins reach their goal
The only other significant thing to me would be to win 12 total with Alumni
Best scenario overall for me would be for Alumni Mixed to go undefeated until I can retire the guild at 12, but that's probably a big stretch unless I decide to put together another iDevice team