I did some digging and found more "sneeze, allergy, sickness," related moments in the series for those interested. No particular order. Mostly older stuff first.
If I Must - TwilightSensitive Much - Twilight (mucus)
Grateful - Twilight (mucus)
Spike Wins - Twilight (messy and snotty, nose play)
Easy For You To Say - Twilight (mucus, stuffed up talking)
"Nose Blowing Conscious" - Twilight (Mucus, nose covering)
"Welcome Autumn" - Twilight (beautifully drawn, snot, nose blowing)
"Springing For Spring" - Twilight (Nose blowing, mucus)
"Furry Fiend" - Twilight (Stuffed talking, mucus)
"Holding Back Fury" - Twilight (Holding back a sneeze/ Stuck Sneeze, great pre-sneeze expressions, not tagged with sneeze though)
"Nature's Bounty - Twilight (Holding nose due to allergy)
"Green Hoofed" - Twilight (Allergic mention)
"Springtime Yardwork" - Twilight (Allergy as excuse)
"Moments of Solace" - Vinyl Scratch (Being sick, red nosed)
"Doomsday Preppier" - Moondancer (coughing)
"Out Cooled" - Moondancer/Starlight Glimmer (Starlight talking about how many times she sneezed, sneezing fit, sneezes in twos, etc, sick Moondancer, not tagged sneeze)
"Friend's Know" - Octavia (Sick, red nosed, tissues)
"To The Extremes" -Twilight and Starlight (Sick Twilight, Starlight telling Twilight to sneeze on her)
"Full Frontal Fantasy" - Twilight (Sick, red nosed, stuffed up talk)
"Waiting Game" - Lily/Starlight (Starlight watching and commenting on Lily's sneezing, saying she has a false start and sneezes three times, also not tagged sneezing)
"Friendly Gift" - Lily (Spike mentions Lily has a cold, but not seen)
"Lily Cares" - Lily (Sick, cold, red nosed, talk about kissing and germs)