Tactical Themes

 Mates

 Annihilation of Defensive Barrier/Obliteration/Demolition of Structure

 Clearance/Line Opening

 Decoy/Attraction/Removal of the Guard

 Defensive Combinations

 Deflection

 Desperado

 Discovered Attack

 Double Attack  

 Double Check

 Drawing Combinations

 Fortress

 Greek Gift Sacrifice

 Interference/Obstruction

 Knight Fork(s)

 Overloaded Defender(s)

 Paralysed Piece(s)

 Pawn Promotion/Pawn Breakthrough

 Perpetual Check

 Pins

 Queen Sacrifice

 Simplification

 Skewer

 Stalemate

 Undermining/Removal of the Guard

 Underpromotion

 Weak Back Rank

 Windmill

 X-ray

 Zugzwang

 Zwischenzug

(from Cyrus Ladkawala)