Absolutely MAASSSSSIVE episode. This was the first canonical on screen depiction of the formation of the “official” birth of the Rebel Alliance. The ships we saw included Phoenix squadron, but also General Dodonna’s group and I believe some Mon Cals
Mon Mothma was a founding member of the rebellion. Where as Bail Organa covertly took action by supplying ships to various rebel factions, Mon Mothma up to this point sought political action. That ended this episode, We saw her in ROTJ, rogue one, and also several Clone Wars episodes
Also, that TIE defender appearance was huge. First on screen appearance of the fighter, which was introduced in the 90s TIE FIGHTER PC games. Filoni has been digging into all reaches of canon far before Mandalorian. This fighter was the best fighter in the galaxy for a long, long time, and was the pet project of Thrawn, as we saw earlier. It is super fast, super maneuverable, heavily armed, and has a hyperdrive. The only downside is cost. Widespread use of this fighter would have ended the Rebellion