The answers to the clues below will have something in common.

1. KPPC,  WNET  - for example
2. Certain kind of painting
3. From one end to the other
4. Popular, having many friends
5. Boys who help cheer girls do stunts

Answers:

1. Radio caLL Letters
2. stiLL Life
3. fuLL Length
4. weLL Liked
5. yeLL Leaders

Credit: NY Times Crossword - Dec. 12, 1990
Richard Silvestri
TRIPLETS

BONUS:
The Llama by Ogden Nash

The one-l lama,
He's a priest.
The two-l llama,
He's a beast.
And I will bet
My silk pajama
There isn't any
Three-l lllama.

[A big fire in Boston?]