What are some must have items that transcend tiers?

[Rizok]

I currently run a group just getting into T9 without any donors, as a result min/maxing is extremely important. Especially as mobs become higher and higher in HPs etc. So what I am looking to make / input on is a list of items that can be obtained to empower your group that may not be your standard armor/weapon/spell upgrades that you get simply by progressing. Things that might take extra consideration to obtain but are well worth the effort to strengthen your group.

Simply put its hopefully a list of items that would be worth returning to prior tiers to obtain from a min/max perspective, even if it wasn't the current tier. I don't have a vast knowledge of T9 items yet so its hard for me to add any of those to this list.

Any input on things I may be missing and can add, or things that I list that may not be best for its given purpose would be appreciated. Going to list what items I have found to be valuable beyond their respective tiers and why I find them necessity. Will update list as I find/think of more things, or as people respond. Work in progress.

Current list:

Misc

Various Threat Click (Legs,Shields,etc that click Anger/Force of Hate/etc)
Power of Fear Ring (there is a few of these through the tiers, DPS Disc)

Pre-Raid Tiers

Healing Automation (Increased Healing)
Kael Tank Gloves (Defensive Discs)
Necklace of Total Order (Group Instant Click)
Shissar Boned Ring (Defensive Disc - Type 8)
Shissar Fang Necklace (FD)

Tier 1

Platinum Mesh Guard (Group Instant Click)
Shissar Empire Badge of Honor (Greater Remove Curse Click)

Tier 2

ToV Quested BP/Legs (Many of these have click effects that do not lose value)
Glowing/Silver Chains (Mana click)
Orb of the Crimson Bull (CoH Click)

Tier 3

Epic 2.0 (Most these clicks are useful even once the item stats become obsolete)
Ring of the Clawed Guardian (Defensive Disc - Type 8)

Tier 5

Symbol Quest Ring (DPS/Tank Discs)
Ring for the Constable (Tank buff)
Resplendent Epaulets (Caster buff)
WoS Quest Pets (Tank/DPS buffs)

Tier 6

Aged Sapphire Adorned Brood Ring (DPS Disc)
Aged Sarnak Channeler Staff (Pet Buffs)
Ancient Crafted BP (Dark Diplomat effect for damage increase/mana reduction)
Staff of the Earthcrafter (clickable fast cast 96% rez)

Tier 7

Dark Chitin Plated Gauntlets (Plate DPS Disc)
Raid Auras (All Buffs)

Tier 8

Statue of Draekon (SHM,DRU,ENC pet w/ AA)
Class BP (Click buffs)
Immaculate Prism of Life (Grp Heal for Shm/Dru)
Dolgrem Ring (Defensive Disc - Type 8)

[Shin Noir]

This post has a MQ2 item info display that can help out a bit: viewtopic.php?f=204&t=9977&p=74646#p74646

Sol Ro Temple's aug, the high AC augs from HoH via djinn, the potions for double godly points (alchemy), the complete heal clickies in Sleeper's Tomb (earring/necklace) warders.. The Plane of Fear clicky for 1s cast time 96% rez, ammo slot, all priest classes, uhm.. tons more.

FD clicky in Shadowhaven, defensive clicky in Shadowhaven,

[Niixnec]

One of the items I use the most for pulling - http://www.thehiddenforest.org/webtools/items.php?id=8165