Assassins: This was a feature present in Warband. Lords who hate you will hire Assassins, who ambush you at night when you enter towns/villages (can only happen once per season to avoid getting repetitive). The battle happens instantly in the settlement scene (increasing the usage of settlement scenes), with the player using their civilian outfit (making that game mechanic more relevant too).
Special wanderers: An NPC marked as "Retired Adventurer" can be found in town/village scenes. These are wanderers with better stats than the ones you can find in taverns. Retired Adventurers do not show up on the world map town menu (encouraging you to explore the scene). You can do this once per season in each settlement.
Collect Taxes / Riot: A similar quest existed in Warband. Nobles can give you a quest to collect tax in a particular town/village. You wait there for a while as you gather money; the larger your party is, the quicker you gather (making this quest worth doing in the vassal phase). There is a chance the citizens will complain about being taxed too much, with the option to tax them less (lowers Honor and relation with lord, but increases Generosity and relations with fief), or force them to pay the remaining taxes, which will cause a riot fight inside the town/village scene, with the citizens attacking you and a handful of your troops in a fight using blunt weapons and civilian outfits.
Charity: An NPC marked as a "Beggar" can be found in towns/villages, asking for charity. You can choose to give them denars for a reward of Generous trait gain and relations with the settlement (reward scales with your clan tier, making it worthwhile to do even in the mid/late game). Once you have paid the Beggar, none will spawn in that settlement for 10 days (encouraging you to explore other locations). A similar feature was present in Warband.
Bargain: An NPC marked "Bargain Trader" can be found in towns/villages. They will offer a trade good for cheaper than the market price. The amount of goods available scales with your Trade level, making this worthwhile even in the mid-late game. You can do this once every 10 days in each settlement.
Arbitrate a Dispute: Two NPCs marked as "Quarrelers", who are having a dispute, can be found in towns/villages. You can use dialogue to persuade them to compromise, gaining Charm and Leadership XP which scale with your clan tier, and relations with the settlement. You can do this once every 10 days in each settlement.
Duel: An NPC named "Belligerent Duelist" can be found in towns/villages, and will challenge you to a duel. If you accept, both of you duel right there using civilian weapons (making civilian outfits more relevant) until one of you is knocked out. Winning gives a good amount of XP scaled with your level. You can do this once every 10 days in each settlement.
Practice Medicine: An NPC marked as "Sick Person" can be found in towns/villages. They tell you they are ill in some way. You can guess a good treatment suggestion from 3 dialogue options, and if you guess correctly, gain Medicine XP for an amount scaled to your existing Medicine skill, providing an alternate way of leveling Medicine. You can do this once per day in each settlement.
Book Seller: An NPC marked as "Book Seller" can be found in town squares, and sells book items which can be read to benefit your skills. Warband had a similar feature.
Battle for the Streets: This feature was present in Warband. Once you had captured the walls of a town in a siege, the siege would move to the streets section of the town scene, and some of the remaining defenders would attempt to hold you off in the streets in a brief smaller-scale fight.