Electric/Fire: Electric Covers Water
Electric/Water: Water covers Ground
Water/Rock: Water covers Ground
Water/Ice: Ice covers Grass
Water/Poison: Water covers Ground
Water/Flying: Water covers Rock
Ice/Ground: Ice covers Grass
Ice/Grass: Ice covers Flying, and Grass covers Rock
Ice/Dragon: Ice covers Dragon(I mentioned this one because the Dragon is not the coverage)
Fighting/Bug: Bug covers Psychic
Fighting/Grass: Fighting covers Ice
Fighting/Rock: Fighting covers Steel
Bug/Poison: Bug covers Psychic
Bug/Grass: Grass covers Rock
Ground/Rock: Ground covers Steel, Rock covers Ice
Ground/Bug: Ground covers Fire
Ground/Grass: Ground covers Fire
Ground/Steel: Ground covers Fire
Ground/Electric: Electric covers Water
Flying/Rock: Rock covers Ice
I can not think of any more, if someone does please comment.