Djinn (Air Genies), Invisible Stalkers, Cloud Giants, Sylphs.
A coastal trade route is being terrorized by "Drowning Ghosts"—undead fueled by a corrupted Water Weird. The PCs must travel to an underwater grotto where the pressure increases every turn unless they can find the "Pearl of the Abyssal Lung." The Quintessence: Combining the Four Earth, Air, Fire and Water (AD&D 2nd Ed Fantasy...
Reward Priests (Clerics/Druids) who use "Sphere" magic (like the Sphere of Elemental Air) by giving them minor bonuses when they are on their "home" element’s turf. Djinn (Air Genies), Invisible Stalkers, Cloud Giants, Sylphs
Marid (Water Genies), Tritons, Water Weirds, Kraken. Marid (Water Genies), Tritons, Water Weirds, Kraken
A city floating on enchanted clouds is slowly losing its altitude. The party must secure a "Breath of Akadi" from a Djinn noble, which involves a high-stakes social negotiation or a race across floating platforms while being harried by Belker smoke-monsters. III. Fire: The Consuming Flame