A clenched teeth emoticon that could be seen as gritting teeth "incoming damage, this might sting" and also bared teeth "now I'm angry/coming for you" Would probably suit a frontliner best, my pick is Asana since her Retribution seeks damage and she is the Angel of Vengeance.

Trashcan emoticon there is an image of a closed metal garbarge can and then the lid is raised by a head that peeks out. I originally thought Oz might be good, but mostly so you could call him Ozcar the Grouch. Then I thought Dr. Finn might be better because an eel could peek out around the bottom corner in the role of Slimey, Oscar's pet worm.
I know Finn has :fishy: so isn't it a little redundant to put him in the trash? I don't want to badnose the doctor, but someone should inform him about his odor #alldayfishmarket

This one might be too character specific but I'd like a Pew Pew emoticon featuring Rio. An image of Rio raining down an infinite loop of drone potshots. Obviously you'd use it when Rio delivers its patented deathblows, but you might also use if if a whole team were to focus fire on one lancer, or on long/concealed shots, or if a character is weakened, attacking someone behind cover, and the 8 dmg still manages to get a kill.