Grand Duke's Shock Trooper - combos with Gaia Gem Monk SS if you want something like Shelby - Song Sorceres other than that it works with Disarment or in some situations with Aug Sorc and other AT manipulation cards.
"One disengaged enemy unit gets AT-20 for this turn. If that unit is at AT0, return it to the File and you get 2 less SP at the beginning of next turn."
Folrart Psycho Soldier - it is random but if you are running a file like HK Lap your units will always be AGI 2 or lower. If your opponent doesn't have any AGI 3+ units you could add a Sylph.
"[conditional use/Refess LV3 or higher] Return one random disengaged unit of AGI 3 or higher to the File. And then you get 1 less SP at the beginning of next turn."
Solar General / Zagar - his ss is really good if you are using units like Guardian
"Revive one friendly Refess unit. Subtract that unit's HP directly from the MAX HP of one disengaged enemy unit."
Moonlight Princess / Eskatia - her ss works really good with open damage and the best sphere for it is gowen
"Return one Closed unit to its card File. And then, you get SP+2."
I like Ariete's Soul its so evil "Move all enemy units to random areas and engage them." Fellana's soul is also great "Engage one disengaged friendly unit, and then Engage 2 disengaged enemy units. Rival Iczer gets 1 less sp at the beginning of next turn."