This is all the PG Bosses that i could find. This is excluding duplicates as many were the same as before.

Music: 【PSO2】7thオープニング （As One）フルバージョン【戦闘BGM】
   • 【PSO2】7thオープニング  （As One）フルバージョン【戦闘BGM】  

Timestamp:
0:00 - UNLEASHED Gundam
1:14 - Hashmal aka IBIS-off-from-wish
2:27 - Unicorn Gundam
3:49 - Apsaras II
5:32 - 00 Raiser
6:55 - II Neo Zeong
8:23 - Big Zam
9:43 - Dong Zhuo Providence Gundam/Dragon Form
11:40 - Burning Gundam/Unicorn Gundam
14:28 - Mega Size UNLEASH Gundam
16:10 - Dark Gundam