Bastion's Resounding Thunderclap

Slamming your hands together produces one of several effects: 

Knuckle Slam - You slam your knuckles together creating a sphere of thunderous force that bursts around you in a 10 foot radius sphere.  Creatures in this radius must make a Constitution saving throw.  On a failed save, creatures suffer 1d8 thunder damage and be pushed 20ft back and are knocked prone.  On a successful save they take half of the damage and get pushed only 10ft.   

Vertical Clap - You clap your hands together and a thunderous arc of sound creates a vertical arc of force striking all creatures along a vertical line ahead and above you that extends to 15ft from you.  Targets must make a Dexterity saving throw or take 3d6 thunder damage, with half damage on a successful save.  Further, targets must make a Constitution saving throw or be pushed 15 feet back.  

Horizontal Clap - You clap your hands together and a thunderous arc of sound creates a horizontal arc of force striking all creatures ahead of you in along a15ft horizontal line.  This force extends to 15ft from you.  Targets must make a Dexterity saving throw or take 3d6 thunder damage, with half damage on a successful save.  Further, targets must make a Constitution saving throw or be pushed 15 feet back.  

Hammer Blow - Grasping one fist in the other hand you swing them together gathering thunderous force during the swing.  Make a melee spell attack against one target, on hit, the target suffers 4d8 thunder damage and must make a Constitution saving throw or be pushed back 20 feet and be knocked prone