Witch Hunter: Where to begin? On the fellas' side, the most obvious perpetrator is Xing. He's a mad flirt and Chivalrous Pervert, said to dislike the company of any man but Tasha Godspell. Since his skirt-chasing is an Informed Attribute, the most on-screen flirting we get to see involves him hitting on Tasha. Words and Cooga are a less blatant example — the character notes say they're inseparable, Words is particularly protective of Cooga, and Cooga respects Words more than he does Vihyunrang.
Palgeuk and Vihyunrang have amassed enough Foe Yay to warrant fanart.
On the ladies' side... pick a recurring female character who isn't Halloween. Chances are, she's been Ship Teased with another woman.
Also, Eclipse Shadenon and her teammate Alv Bronte.