From Flame Pegasus, Capricorn Strike G, Thunder Pegasus
From Metal Dragoon Bearing Stinger
(May not actually be brass, but it looks like it)
From SonoKong Dranzer S, possibly other SonoKong releases.
From Bearing Gyros Series, Dranzer F, Driger F, Burning Kerberous and Zeus
Generic MR52ZZ Shielded Metal Ball Bearing (manufactured by NSK in early releases, manufacturer not named later)
Also called Free Bearing, NSK Bearing
From Metal Dragoon Bearing Stinger, Bearing Gyros Series, Wolborg, Wolborg 2, and Burning Kerberous