Pressing B during any moment while charging an attack will cancel the animation. This is useful for two-handed weapon spin attacks.
All standing attacks from all weapon types and charging animations can be cancelled at any moment by jumping.
Swapping weapons/shields during any moment of any attack will cancel the animation completely, even dash attacks or finishers (except grounded jump attacks).
The slowmo animation after parrying an attack with a shield can be cancel at any moment with the crouch animation. This can allow Link to move even earlier after a parry.