Do any Small World expansions lengthen play time?
Most of Small World's expansions (Grand Dames, Be Not Afraid, Cursed) just add additional races and powers. Those won't lengthen the game.


Realms adds a modular board and scenarios. Those will presumably add to the setup time a little, and some of the scenarios might also take longer than an ordinary game.
Tales &amp; Legends adds events, which will take a little extra time to resolve and consider the consequences of.
Tunnels allows you to play with six players and combine the base game with the standalone follow-on game Small World Underground. It's difficult to imagine that both factors wouldn't considerably increase the play time.