So, both as a designer and as a player I prefer fantasy roleplaying games that have a slightly darker backdrop than, say, the Forgotten Realms, which retains its hopeful outlook at all times.
(Not that FR isn’t awesome — I spend a lot of time there — though I usually turn the dial on the darkness setting higher than what appears on the page).
The pseudo-European backdrop of my homebrew setting Steffenhold is a dark fantasy reflection of the pre-Renaissance period.
And Kobold Press’ Midgard, which is steeped in Slavic legends and folklore, filled with imposing ghoul-stocked forests and tricksy gods who never reveal their motivations nor true selves, fits in my wheelhouse.
I’m also up for most Gothic-inspired horror. Baron von Strahd and Count Dracula are fearsome adversaries — plenty of room for heroics in an otherwise ink- and blood-stained milieu.
With that out of the way, however, I’d suggest that gamemasters not forgot that they should always make room for unicorns — or some other symbol of hope — in their fantasy adventures. Let a little sparkling light pierce the darkness.
I use unicorns as an example simply because in film and literature, unicorns were used to good effect in both The Last Unicorn and Legend. In war-torn lands troll- and goblin-filled, the mythical equine beast represents chastity and fidelity, an enduring quality that gives hope to good-hearted folk that they may yet triumph over oppression and tyranny.
But, of course, the maiden’s lure need not be the only bright light in your setting. Consider salting your universe with any of these options if you feel unicorns are a tad to cliche.
Dog. The “master’s hound” has represented fidelity and obedience for centuries, but was a powerful symbol during the middle ages. Dogs of great heroes have been recorded in many legends, King Arthur’s favorite hound was Cavall, and Ulysses’s dog was Argos — who recognized his master from his return from Troy and then died of joy. In fantasy gaming, a hound archon is one of the great celestials.
Elephant. A Danish order of knighthood that once consisted of 30 knights. Although a “white elephant” carries the connotation of a burden, the King of the White Elephant was a title born by the great king of Ava (Myanmar).
Griffin. The offspring of two creatures said to be of noble heritage, the lion and the eagle, the griffin represents valor and magnanimity. The griffin also guards sacred treasures.
Phoenix. This magical beast represents resurrection, a powerful symbol in both ancient times and in the middle ages. The creature also has an association with alchemy.
Serpent. Turning the Semitic/Christian connotation of the tempter on its head, adopt the other characteristics of the serpent — eternal, healing, wise and spiritual guardian — instead. Probably best represented as a coatl, symbol of the Aztec winged serpent Quetzalcoatl.