Lycoris has an ability that in creases all team damage by a % that increases the more enemies you are fighting so is a good AoE Sweaper.
Nerine is very strong for me, I've had her from early on and she hits like a truck.
Saffron and Mistletoe are great counter girls.
Acacia is a nice atk nerf girl.
Viola has an ability that gives your units another type so they do that +50% damage more often.
Cattleya has a really high ATK buff for a few girls that means her own AoE is one of the strongest hitting out there.
Can't remember the rest right now but I have and use Cherry, Iberis, Pumpkin (not yet bloomed but soon) and Burning Bush.