What's the house's name/background?
Smaller than their cousins and crewed by aspiring nobles, low-born commoners with a knack for war, or even the bastard children of Barons and High Kings, Armigers hunt and fight at the flanks of their larger kin.
We don't know if armigers are considered knights named in the same way, but if they are, some suggestions
Venator Mechanicum (Mechanicum Hunter)
Secuutur Martis (Pursuer of Mars)
Equites Ferrum (Steel Rider)