I believe that not-to-be-missed by-name items will disappear quickly in later expansions. I can name a few wotlk items, maybe 2-3 cata items but nothing more than the Burning Crusade Classic Gold expansion, excluding the maledict trinket which wasn't notable for any reason...
For me 2-healing NB, I just pot early back up to near the full mana level, and then shadow friend in the 2nd phase of ground The pot CD is returned before the end of battle if needed. I also have runes, but I don't use them unless I am in SHTF.
This is the way I do , too, when running with my guild where I know my teammates. I've noticed that the bangle is nice for pugs. It helps when a tail swipe occurs that causes people to stand in shit for too much, less powerful healer than what I'm used too, and a chaotic air phase.
Trinkets from Healer are rather uninspiring P1. I'm still using Essence of the Martyr and Rejuv Gem as my main choice gem, and I only switch Rejuv Gem out for Eye of Gruul on Mag trash or (formerly) Blue Dragon on Nightbane. There are Bangle the Warp-Scarab brooch and Bangle. However, neither of them is extremely powerful.
You can replace them, but you'll still fall back on the cap for expertise in the event that you do, since the legs that are off set and the t5 ones don't have 22 expertise. The majority of pallys are in agreement that they'll be moved around for a time.
If you're able to get all three and you're a human you take the pants off for a moment, but it's advised to hold the three pieces as a transitional piece when gearing up in the p3. I do not know how other animals handle it and maybe they never get them off. I'm just not certain.
The healing mace "Trauma" for my resto shaman .... and watching the screen turn green with a million little heals going out .... that was my favourite.
Edit Trauma and the Glowing Twilight Scale .... because the healing of chain heal was thought to be a direct healing regardless of subsequent hops, which would cause both of these items to run in an erratic manner, and I could literally be healing 20 or 25 people in the raid at any time.
Edit Edit: And the 4 pieces of the Tier 10 armor which caused the chain's target healing crits to also heal for an additional 25% of the healing over the course of time. This cheap WOW TBC Gold is in addition to the incredible output you could get as an astro-shaman.