Steam Engine - Each consecutive turn a damage dealing attack lands, the base damage of damage dealing attacks increases by 10%, if it fails to land a damage dealing attack, the base power of damage dealing attacks reverts to 80%.
Ex: Magnezone with Steam Engine
Turn 1, Magnezone uses Flash Cannon (80 power) - 100%
Turn 2, Magnezone uses Thunder (132 power) - 110%
Turn 3, Magnezone uses Signal Beam (90 power) - 120%
Turn 4, Magnezone uses Thunder, but it missed!
Turn 5, Magnezone uses Flash Cannon (64 power) - 80%
Turn 6, Magnezone uses Thunder (108 power) - 90%
Turn 7, Magnezone uses Thunder Wave -N/A-
Turn 8, Magnezone uses Signal Beam (60 power) - 80%
Only'd make sense for a few pokemon off the top of my head though. Magnemite Family, Klink Family, Probopass.