What if dragon-sightings and evidence of such was treated with the same skepticism and mockery as modern UFO sightings? More for a low magic world where dragons 'dont' exist.
The PCs encounter a strange set of artistic drawings done on the ground as they pass through a city. It has been done in chalks and no one saw who did it. Wizards might recognize the writing within the colored square as an obscure and dead language with a message stating that a prominent wizard and a retired bard have discovered how to populate Arcadia with the spirits of the dead!
Is it a local hoax, or are the PCs crossing the path of a very deranged and possibly dangerous mage?
Enraged by the violation of the Peace Pool and the Whalebone Forest, a dead leviathan has risen from the bottom of the ocean and now hounds ships around the port where the stolen jewels went to land. It capsizes ships and devours sailors whole, spears protuding from its dead and crab-eaten hide.
Game Cliche 2.
Upon learning about "the five ancient jewels" or "the nine legendary icons" or whatever, you can be quite confident that Saving the World will require you to go out and find every last one of them.
Game Cliche 1.
All legends are 100% accurate. All rumors are entirely factual. All prophecies will come true, and not just someday but almost immediately.
After a long night of reveling and merriment celebrating their latest victory, one of the PCs awakens with his/her head shaved and a large ornate tattoo on top of their head. Tacky, yes but also a painstaking work of art that has left them with a headache to beat their hangover. The kicker? It is a huge symbol of the god of Evil, Assassins, the Drow, Munchkins, something really really offensive
The PCs are invited to play in lumberjack games. They must see how quickly they can cut down a tree, how quickly they can use a great saw to cut a wheel from an already dropped tree, and must stay on top of a floating log while a lumberjack tries to roll the log to make them fall in the water. The winner gets beer and pancakes
Nearly every primitive culture has had rituals and celebrations to guarantee the proper passage of the seasons and to ensure the fertility of crops and animals. Oversight of these ceremonies was generally the provenance of local kings or priests.
Suppose that the adventurers dispatch one of these fellows. The local peasants may become hysterical, fearing famine and death will stalk the land. Alternatively, they may want one of the new heroes to become king. For a while, this can be a good thing, but the first time that the crops fail, the superstitious locals will want to sacrifice their new leader.