It's probably not a big secret that I really like the Fafhrd and Grey Mouser books by Fritz Leiber. I didn't initially like them very much, but I grew to like them over the years. They've influenced my games and my approach to gaming.
And thus, they've influenced Dungeon Fantasy. Here are a couple of things I helped get inserted into DF as homages to Fritz Leiber's duo.
GURPS Dungeon Fantasy Denizens: Barbarians contains a Leiber quote. But it also features the Civilized Savage lens. Want to make a smarter barbarian smitten with the charms of civlization? Perhaps a tall, red-headed one with a long sword, a large knife, and a rougish companion? The Civilized Savage was created to allow for a better modeling of Fafhrd using DF Templates.
GURPS Dungeon Fantasy Denizens: Swashbucklers is one of Sean Punch's excellent books. I was allowed to review it. The expanded versions of Weapon Bond were there . . . but what about rougish types who steal replacement blades and then wield them like extensions of their own arms? The duo do exactly that - they always steal replacements for their weapons. Weapon Bond (Rougish) is meant to model that, but with a "found as loot" twist to make it better fit to dungeon delving and the slay-and-loot style of play that DF explicitly espouses.
So not only my games, but also those of people who use those books, have a Leiber influence on them.