1-2. school daze
3. the maud couple
4. fake it 'til you make it
5. grannies gone wild
6. surf and/or turf
7. horse play
8. the parent map
9. non-compete clause
10. the break up breakdown
11. molt down
12. marks for effort
13.
the mean 614. a matter of principals
15. the hearth's warming club
16. friendship university
17. the end in friend
18. yakity-sax
19. on the road to friendship
20. the washouts (episode)
21. a rockhoof and a hard place
Okay, technically that is an error from a procedural (or whatever) perspective, but it looks cool and somepony COULD make a helmet that looks like that, so, personally, I’m not going to count it.
I believe it’s the middle guards helmet. It has a double fan on the top