"Elf" (エルフ Erufu) is an archetype used by Gekko Tenma in Yu-Gi-Oh! R, with a few members also used by Yugi Muto and Yuma Tsukumo. They are mostly LIGHT/EARTH Fairy/Spellcaster/Warrior monsters. This archetype has support in both the anime and manga.
In Yu-Gi-Oh! The Duelists of the Roses, "Wing Egg Elf" can transform into a monster with "Elf" in its name when strengthened with "Insect Imitation". In Yu-Gi-Oh! Forbidden Memories, "Celtic Guardian" can be Fusion Summoned using an "Elf" and a Warrior monster. Also, in both video-games, "Elf's Light" can only be equipped to "Elf" monsters.