Here's one I made up. What do the following words have in common? The answer isn't that they have eight letters, or all have a "p," though those are sort-of clues.

captions
biplanes
elapsing
clasping
quiplets
pleasing
pralines
pastime
Okay, this is probably too obscure without some help. So, as the Yellow Pages say, let your fingers do the walking.
Each word has the letters s, i, p, and no repeating letters.