Sure, i can make such list. Not sure though if it will be usefull in tbc - debuffs like locust swarm or wrath of plaguebringer is unique. But some names reused by blizzard quite often. First debuff that comes to mind is Mind Flay (many mobs has it, and generally it kills very quickly,so target needs heavy healing)
Well, there probably are quite a few debuffs, and some of them arent of the 4 types we can dispel but still are relevant (mortal strike as one example - which either currently doesnt work or just no mob in MC ever casts it). Some ideas:
Mortal Strike -50% healing
Mortal Cleave -50% healing
Gehennas\' Curse -75% healing
Curse of the Deadwood -50% healing
Blood Fury -50% healing -50% healing
Brood Affliction: Green -50% healing
Necrotic Poison -90% healing
Conflagration 3000 dmg over 10sec
I currently cant provide the best concept to deal with all these debuffs (plus probably another 10-15 if we think hard) that all are related to raid dungeons. Personally I'd want them all to be displayed as center icon (while the less relevant stuff that needs clearing is displayed as border in my current setup). In other words this is just a suggestion for a future module or enhancement without really knowing how it should look yet - with the main idea that not every casual raider has to add them all himself. Any ideas?
Are there really many boss scenarios in the game where multiple debuffs of a specific type (magic, disease, etc) are used during an encounter? From a priest point of view, the only one that comes to mind is the lab packs in BWL, where the felguards cast Thunderclap and the Blood Elf sorcerers (?) cast Greater Polymorph. In that case, I'd like to ignore Thunderclap (or at least not see it's icon in the center of a Grid frame) but would most definitely want to see a Polymorph Icon.
If you're looking for a complete list of debuffs that would be beneficial for healers to know of (ie, display on a Grid unit frame), check out Simply Magical Healer (SMH) on WoW Interface. I spent alot of time testing that and providing the author with effect names to take into account. As of October, it was up to date with all boss encounters through Naxxramas.