Sellsword Companies
In AWoIaF, you can recruit various sellsword companies or parties that roam the map, or kill them to remove opposition. Some of these will loot and raid villages.
In order to recruit them, you must engage a conversation with them and choose to hire them. If your relationship with their faction is too low, they will not agree to your terms and attack instead. You must have space for their entire army to join you and sufficient money in order to recruit them. Because of need for space, choosing to talk to them can pose quite a risk if you have a negative relationship as you'll often need to engage with a smaller army.
Windblown
Acquisition
They can be found near Lorath
Stormcrows
The Stormcrows are 502 unit large troops entirely comprised of Veteran Freeriders and 2 unique units. Their leader is Prendahl na Ghezn.
Acquisition
They can be found near Myr and costs 100,000 to hire.
Moonbrothers
Acquisition
They can be found near Gates of the Moon and often roaming towards Moat Cailin
Wild Hares
Acquisition
They can be found in the North
Second Sons
The Second Sons are 503 unit large troops entirely comprised of Veteran Freeriders and 3 unique units. Their leader is Mero.
Acquisition
They can be found near Volantis and costs 120,000 to recruit.