Knights-
Rapiers
Battle Axe
Falchion
Mace
Hammer
Pole Hammers
(Suggestion the pole arms for the Captains since we've already seen on in the story mode)

Vikings-
Rebar Axe
(Pretty interesting looking)
Nothing else I could really find for this

Samurai-
Bow and arrows (Actually were known to be better at the bow on horse)
Two Swords or Daisho and the Wakizashi
(Wakizashi was known for cutting off the opponent's head and for Seppuku and which another samurai stood by to behead the person for a quick death. Hinting to use this as an execution)
Matchlock Firearms
(Recommend as a feat)
Chains and Weights
(Not really needed since we already have the Shinobi)
Truncheons


I could show a picture for each one, but this was just hinting at some possible weapons to use for any character that might pop up.