Here's the damage output for every attack.
White - Vanilla
Blue - Speed
Yellow - Shield
Purple - Buster
Red - Smash
+/- 0% Damage
Neutral combo- 3% first hit, 3% second hit, 4% third hit
Forward tilt- 12% base, 10% tip
Down tilt- 8% base, 6% tip
Up tilt- 7% base, 6% tip
Dash attack- 10%
Ledge attack- 7%
Forward smash- 5% first hit, 12% second hit uncharged; 7% first hit, 17% second hit fully charged
Up smash- 4% first hit, 13% second hit uncharged; 5% first hit, 18% second hit fully charged
Down smash- 13% uncharged; 18% fully charged
Neutral aerial- 6% base, 7% blade
Forward aerial- 6% base, 5% tip
Back aerial- 11% base, 7% tip
Up aerial- 4% first hit, 9% second hit
Down aerial- 6% first hit, 10% second hit
Pummel- 3%
Up throw- 2% first hit, 4% second hit
Down throw- 2% first hit, 4% second hit
Forward throw- 2% first hit, 8% second hit
Back throw- 2% first hit, 9% second hit
Back Slash- 9% base, 10% blade front; 14% base, 16% back
Air Slash- 5% first and second hit
-20% Damage
Neutral combo- 2% first hit, 2% second hit, 3% third hit.
Forward tilt- 8% base, 7% tip
Down tilt- 6% base, 5% tip
Up tilt- 5% base, 4% tip
Dash attack- 8%
Ledge attack- 5%
Forward smash- 3% first hit, 9% second hit uncharged; 5% first hit, 12% second hit fully charged
Up smash- 2% first hit, 11% second hit uncharged; 5% first hit, 13% second hit fully charged
Down smash- 9% damage uncharged; 13% fully charged
Neutral aerial- 4% base, 5% blade
Forward aerial- 4% base, 3% tip
Back aerial- 7% base, 5% tip
Up aerial- 3% first hit, 6% second hit
Down aerial- 4% first hit, 7% second hit
Pummel- 2%
Up throw- 2% first hit, 3% second hit
Down throw- 2% first hit, 3% second hit
Forward throw- 2% first hit, 5% second hit
Back throw- 2% first hit, 6% second hit
Back Slash- 6% base, 7% blade front; 10% base, 11% blade back
Air Slash- 3% first hit, 4% second hit
-30% Damage
Neutral combo- 2% first hit, 2% second hit, 3% third hit
Forward tilt- 8% base, 7% tip
Down tilt- 5% base, 4% tip
Up tilt- 4%
Dash attack- 7%
Ledge attack- 4%
Forward smash- 3% first hit, 8 second hit uncharged; 5% first hit, 12% second hit fully charged
Up smash- 2% first hit, 11% second hit uncharged; 4% first hit, 12% second hit fully charged
Down smash- 9% uncharged; 12% fully charged
Neutral aerial- 4%
Forward aerial- 4% base, 3% tip
Back aerial- 7% base, 4% tip
Up aerial- 3% first hit, 6% second hit
Down aerial- 4% first hit, 7% second hit
Pummel- 2%
Up throw- 2% both hits
Down throw- 2% both hits
Forward throw- 2% first hit, 5% second hit
Back throw- 1% damage, 6% second hit
Back Slash- 6% base, 7% blade front; 9% base, 11% blade front
Air Slash- 3% first hit, 4% second hit
+40% Damage
Neutral combo- 4% first hit, 4% second hit, 6% third hit
Forward tilt- 16% base, 14% tip
Down tilt- 11% base, 8% tip
Up tilt- 9% base, 8% tip
Dash attack- 14%
Ledge attack- 9%
Forward smash- 7% first hit, 17% second hit uncharged; 9% first hit, 24% second hit fully charged
Up smash- 5% first hit, 18% second hit uncharged; 7% first hit, 25% second hit fully charged
Down smash- 18% uncharged; 25% fully charged
Neutral aerial- 8% base, 9% blade
Forward aerial- 9% base, 7% tip
Back aerial- 15% base, 9% tip
Up aerial- 5% first hit, 12% second hit
Down aerial- 8% first hit, 14% second hit
Pummel- 4%
Up throw- 3% first hit, 5% second hit
Down throw- 3% first hit, 5% second hit
Forward throw- 3% first hit, 11% second hit
Back throw- 3% first hit, 12% second hit
Back Slash- 12% base, 14% blade front; 19% base, 22% blade back
Air Slash- 7% first and second hit
-50% Damage
Neutral combo- 1% first hit, 2% second hit, 2% third hit
Forward tilt- 6% base, 5% tip
Down tilt- 4% base, 3% tip
Up tilt- 3%
Dash attack- 5%
Ledge attack- 3%
Forward smash- 2% first hit, 6% second hit uncharged; 3% first hit, 8% second hit fully charged
Up smash- 2% first hit, 6% second hit uncharged; 3% first hit, 9% second hit fully charged
Down smash- 6% uncharged; 9% fully charged
Neutral aerial- 3% base, 3% blade
Forward aerial- 3% base, 2% tip
Back aerial- 5% base, 3% tip
Up aerial- 2% first hit, 4% second hit
Down aerial- 3% first hit, 5% second hit
Pummel- 1%
Up throw- 1% first hit, 2% second hit
Down throw- 1% first hit, 2% second hit
Forward throw- 1% first hit, 4% second hit
Back throw- 1% first hit, 4% second hit
Back Slash- 4% base, 5% blade front; 7% base, 8% blade back
Air Slash- 2% first hit, 3% second hit
I used both caluculations and actual testing in the game, but if you see any inconsistencies don't be afraid to ask. Also the global percentage I listed is an estimate based on the results.