Swellow learn Brave bird in B2 breeding with some of these male´s Starly, Starivia, Staraptor, Farfetch´d Rufflet, Braviary, Sigilyph, Pidgey, Pidgeotto, Pidgeot with Female Swellow.
In X and y you need to breed with a male Noivern to get BoomBurst.
Source Serebii