Pony!
which is the strongest piece?

But wait! What about the amazon-rider? It moves like amazon or knight-rider, and like the archbishop and amazon, can Checkmate a bare king.

I think arguments can be made for the King. The king is mentally the strongest. He knows that hiding is a good idea; but when push comes to shove, he comes sneaking out of his hiding spot to get the job done himself.
Even if the endgame is comically one-sided, it's still an incredible thought. Imagine being in an actual battle, and suddenly the king shows up and starts causing problems. That would throw people off.

It's pawn, knight, or queen for me.
Pawn- It's expendable, which makes it very useful.
kNight- No other piece moves like it, it can attack any other piece while out of danger.
Queen- The combined movement of the rook and bishop, it is the piece that the fewest pieces can safely attack

Look, the simple answer is... What type of chess? Spell chess, torpedo chess, chess960, bug house, ghost chess....
Bro thinking outside the box