Right now there aren't a lot of people using Swan Cavalier's open skill, but there are quite a few cards that hit all cards. Salamander's soul skill hits level 3s and below, Falkow Grimoire Tempest hits everyone for 30, Broken Iron Soldier XXXX's soul skill hits all cards level 3 and below.
Might as well toss in the rest. Fire Storm Wyvern's Soul Skill does 20 to everything, Fire Storm / Bander's Soul Skill does 30 to everything, Lycanthrope / Legion's Soul Skill hits things with Agility 2 or less. And Broken Soldier also has an ability where he does 50 to everything.