Lower Chest:
Easy: incline pushups
Medium: feet Supported chest dip
Hard: unsupported chest dip

Mid-Chest :
Easy: knee Pushups
Medium: standard push-ups
Hard: Archer Pushups

Upper Chest:
Easy: bent knee upper chest pike Pushups
Medium: upper chest pike Pushups
Hard: decline Pushups

Squeeze:
Easy: doorway single hand squeeze pushups
Medium: close grip pushups
Hard: Twisting Archer Pushups