There are few limits to what might inspire a fantasy TTRPG seed. This site started with me trying to come up with a good one-shot while listening to music. Song titles and lyrics can be fun idea generators. Some musical styles might work better than others. Metal might make more sense than pop, but they can all work.
My process is to start with the song title or lyrics. Then I brainstorm potential seeds. For example, here is a seed inspired by a couple of lines from a Taylor Swift song. Which song? I sincerely do not remember.
The party comes upon an underground pond. The water is exceptionally clear. It is also exceptionally deep. There is something shiny on the bottom.
Here is a seed inspired by lyrics from the hit Foolish Beat by the 1980s popstar, Debbie Gibson:
A wizard is desperate for help from anyone who will listen. Her lover wanted to sprout wings, but when the wizard cast the spell, it turned the lover into a dragonfly. She has him in a jar on her desk and thinks she might know a way to turn him back.
Go check out those lyrics and see if you can find the lines that inspired this!
How about another example? Here is House of Shame by Lacuna Coil.
The song begins with two one-word line:
Run.
Rise.
With only these two lines (two words), we have plenty to develop an interesting fantasy TTRPG seed.
As the party walks through a settlement near the village cemetery, a nicely dressed man looks at the party, smiles, and casually says, “Run.” Then he turns toward the cemetery, lifts his hands, and shouts, “Rise!” The ground begins opening beneath the surface of the cemetery.
That sets up an encounter, one-shot, adventure, or even a full campaign. As an encounter, six or ten or twenty zombies rise from the graves. This would be a classic undead combat battle. This would also make for an easy start to a one-shot. The party might retreat a bit being outnumbered then join forces with the town guard or local peasants to find the necromancer (if he is a necromancer) and fight against the hoard. That might take a few sessions due to complications that arise. Now, there’s an adventure! Finally, this could be the introduction to the villain for a full campaign. The direction this goes depends on the GMs desires and the characters’ actions. It started from a two-word song lyric.
The next two lines are a bit more detailed:
Burn me, reducing the stigma.
Born to live in this house of shame.
How can that not inspire you? There are so many directions to go with those two lines! After coming up with the seed, I germinate the seed with secrets. This is largely inspired by Mike Shea’s tips. I write secrets freely, even when one secret contradicts another. This is merely a brainstorming phase. I will select certain secrets that make sense for the game I am playing. Finally, I grow that into an encounter, adventure, or campaign.