bishop and rook is taken out due to the queen being able to cover both and being more versatile. it's a great thing to have fun with tho.
Underpromotion

I believe in the "minimum necessary" school of pawn promotion. Why promote to a Queen when a Rook will mate in one? (Such as when the King is trapped on the back rank).
Sometimes less is more.

I believe in the "minimum necessary" school of pawn promotion. Why promote to a Queen when a Rook will mate in one? (Such as when the King is trapped on the back rank).
Sometimes less is more.
Yeah this from a retarded 1200 lmao thinking a queen can't checkmate

The only time it might make sense to under promote to something other than a knight would be if promoting to a queen would cause immediately stalemate (but rook or bishop is sufficient for win), as part of some handicap, or you are trying to show off. Sounds like you are going for option 3. =)

I've actually had a game here on chess.com where I needed to underpromote to a knight to avoid stalemate(both queen and rook would have resulted). I wish I could find it.

This reminds me of the poor guy in a bullet game that had autoqueen on...
I always keep that option. I never had any problems so far.

Smerdon showed a great study where underpromotion to Bishop was necessary to tie a game. Sometimes the one who is promoting still cannot win, so there are other cases than what have been mentioned.
http://www.chess.com/blog/smurfo/the-most-unusual-move-in-chess-or-quothow-i-won-a-beer-in-my-lunch-breakquot
Many people beleive that the only worthwhile promotions are a queen (obviously), and a knight (for forking purposes.) Others would be so bold as to venture to put the rook in that category, to account for such a position as the below.
However, most people don't think about promoting to the lowly bishop. Why? Because, (1) you can't checkmate w/ K+B (2) if you're trying to avoid stalemate, just promote to a rook (3) If you're trying to avoid checkmate on the diagonal, promote to a queen.
On that note, below are some "underpromotion" puzzles.