Original Mechanics
Rich NPC Interactions
Yu-Gi-Oh: Sacred Cards
The player can interact with NPCs in different ways, depending on the NPC. The player can battle, play cards, trade, or talk with an NPC.
NPC Rich Dialog
Fallout 4
NPCs can have rich dialog, with multiple options for the player to choose from. The player can also ask NPCs about specific topics, and the NPC will respond accordingly.
The player can also conduct ability checks during those interactions, to try to convince the NPC to do something, or to learn more about a topic, among others.
Triple Triad
Final Fantasy VIII
The player can play Triple Triad with NPCs. The player can also collect cards, and use them in battle.
The implementation of Triple Triad is the one provided by Pokemon Essentials