So I think I'll add:
Circle of Stacked Firebats Attacking Object in Center- Eye of Sauron, infernal pit.
Heaped Khaydarin Crystal Formations- Iceburg/Glacier, ice wall, azure rock wall.
Zergling Corpse- Blood stain, blood splash.
Rhynadon Corpse- Green gas puff, heal effect, a fart
.
Wandering Scarab w/ Recall Swirls Following- Great spirit, tornado (?), attack/spell effect.
Yamato Cannon-
(Dabbu for credit) A meteor, shooting star, spell/attack effect.
Plain Scarabs (no movement glows)-
(Dabbu for credit) Gold pieces, small bugs, pieces of treasure.
Placable Ashworld Rock Doodad Sprites-
(Dabbu for credit... as far as I can remember at least) Avalanche rocks.
Cloaked SCV Attacks- Sparking machinery, sparks (genera), small fireworks, laser point.
Dark Templar Death- Misty puff, magician effect, dark spell effect.
Shield Battery + Observer Cloak Blurs + Cloaked Burning Buildings- Campfire.
So, thar ye be. Still looking out for any new ones (or better uses for old ones).
ADDITION:
Hey, could anyone help make me some images or short animations of various effects? I think that would make this a lot more useful to people, when they can see the effects themselves.