50 moves is an older rule. There is at least one position where the game is won but takes more than 50 to apply the force. I am not sure but I thought the rule increased the count over 50.
The second one is fairly well known and happens often (most folks declare a draw agreed without a 50 count for the first rule). I think it should be 3 in a row or 3 within 10 or something. Unlikely but a draw 40 or something moves apart vs an opponent with a photographic memory would be pretty lame and gives an advantage to people with extrodinary memories.
Who would have known? I certainly wasn't aware of this one:
"Fifty consecutive moves have been played where neither player has moved a pawn or captured a piece"*
This one I had an inkling but wasn't certain:
"A player declares a draw if the same exact position is repeated three times (though not necessarily three times in a row)"*
* https://secure.chess.com/learn-how-to-play-chess