I'm going to assume you're not willing to crossplay/dress so...
Lilly and Hanako or Shizune and Misha from Katawa Shoujo.
Patty and Liz from Soul Eater (Bonus if you can get a 3rd to be Kid)
Mariya and Matsurika from Maria Holic
Any two female Vocaloids
and the list goes on and on
Gakuen Hetalia, Prussia (Shado 12)
Pokemon, Gold/Ethan (Shado 12, Metro 13)
Vocaloid, Dell Honnie
Batman, Black Mask (Khaotic 14, Metro 14)
Soul Eater, Spirit/Death Scythe (Shado 12, Metro 13)
Hetalia, England Cd (Metro 13, Khaotic 14)
Team Fortress 2, Blu Spy
Soul Eater, Giriko (Metro 14)
Baccano!, Maiza Avaro (Metro 14)
Pokemon, Giovanni (Khaotic 14)