The rook pawn is the hardest to convert: the attacking king has no shelter on the far side, so the defender's checks never run out as long as the king stays away from forks.
Queen and pawn versus queen with a rook pawn is the most drawish version, because the pawn offers shelter on only one side. White's king on a7 and pawn on a6 look menacing, but the black queen on a1 checks along the a-file and the long diagonal, and the white king has nowhere to hide: b8, b7, b6 are all exposed to checks from the first rank, the long diagonal or the b-file.