Feather

Click here for visual deck (with images)
Click here for my EDH Commander decks
 
• Damaging instants/sorceries that let you split up the damage. You target your creature for 1, and the rest on the opponent or opponent's creatures.
• Creatures that do something when they're targetted.
• Other instants/sorceries that let you split up the effect, like "tap X creatures".
I didn't research Feather decks at all; this deck could be missing some obvious (commonly played) synergy with Feather. I was just going for the above themes.
 
Mana Acceleration (14): General (1): Spells (35): Sideboard (Omitted/Cut card ideas):
1 Boros Keyrune 1 Feather, the Redeemed 1 Sphinx-Bone Wand 1 Volcanic Salvo
1 Cloud Key   1 Aurelia's Fury 1 Sundering Stroke
1 Gold Myr Creatures (14): 1 Captain's Maneuver 1 Rally the Righteous
1 Hedron Crawler 1 Anax and Cymede 1 Intimidation Bolt 1 Splicer's Skill
1 Iron Myr 1 Tenth District Legionnaire 1 Balduvian Rage 1 Fall of the Titans
1 Manakin 1 Akroan Conscriptor 1 Chandra's Ignition 1 Volley of Boulders
1 Palladium Myr 1 Akroan Crusader 1 Comet Storm 1 Spreading Flames
1 Primal Amulet // Primal Wellspring 1 Labyrinth Champion 1 Commando Raid 1 Downhill Charge
1 Pyromancer's Goggles 1 Akroan Skyguard 1 Fall of the Hammer 1 Enrage
1 The Immortal Sun 1 Angelic Protector 1 Fight with Fire 1 Violent Eruption
1 Jaya Ballard 1 Dawnbringer Charioteers 1 Ghired's Belligerence 1 Blessed Breath
1 Sisters of the Flame 1 Elite Skirmisher 1 Gravitic Punch 1 Feat of Resistance
1 Path to Exile 1 Leonin Iconoclast 1 Harness by Force 1 Wave of Indifference
1 Sunseed Nurturer 1 Phalanx Leader 1 Jaws of Stone 1 Twinflame
  1 Setessan Battle Priest 1 Meteor Blast 1 Meteor Shower
Lands (36): 1 Vanguard of Brimaz 1 Rolling Thunder 1 Jaya's Immolating Inferno
1 Plateau 1 Wingsteed Rider 1 Soul's Fire 1 Into the Maw of Hell
1 Sacred Foundry   1 Volcanic Wind 1 Tail Slash
1 Rugged Prairie   1 Wild Swing 1 Deadshot
1 Clifftop Retreat   1 Adamant Will 1 Conflagrate
1 Akoum Warrior // Akoum Teeth   1 Ajani's Presence 1 Blinding Flare
1 Arcane Lighthouse   1 Blessed Alliance 1 Stave Off
1 Detection Tower   1 Blinding Beam 1 Gods Willing
1 Emeria's Call // Emeria, Shattered Skyclave   1 Collective Effort 1 Apostle's Blessing
1 Forbidding Watchtower   1 Ephemeral Shields 1 Bathe in Light
1 Ghitu Encampment   1 Fell the Mighty 1 Reckless Rage
1 Myriad Landscape   1 Glimpse the Sun God 1 Punish the Enemy
1 Needle Spires   1 Graceful Reprieve 1 Barbed Lightning
1 Nykthos, Shrine to Nyx   1 Launch the Fleet 1 Kor Chant
1 Ondu Inversion // Ondu Skyruins   1 Orim's Thunder 1 Hungry Flames
1 Sejiri Shelter // Sejiri Glacier   1 Settle Beyond Reality 1 Lunge
1 Shatterskull Smashing // Shatterskull, the Hammer Pass   1 Shelter 1 Boros Charm
1 Skyclave Cleric // Skyclave Basilica   1 Sheltering Light  
1 Spinerock Knoll   1 Survive the Night  
1 Thawing Glaciers   1 Valorous Stance  
1 Valakut Awakening // Valakut Stoneforge      
1 Windbrisk Heights      
7 Mountain      
7 Plains      
1 Sol Ring