This is a list of clickies that make you invulnerable for 3 ticks (18 seconds).
Cursed Rage Channeler
Recast Delay: 8 hours
Random drop in instances of Bloodmoon Keep (both group and raid)
Feral Guardian Channeler
Recast Delay: 8 hours
Random drop in Snarlstone Dens: Confronting a Traitor
Totem of the Wurines
Recast Delay: 8 hours
Random drop in The Hive: Freeing an Elder, ONLY in the low level version (65 and under) of the task
Earring of the Frozen Skull
Charges: 4 (not rechargeable)
Reward from Coldain Ring #10: Ring of Dain Frostreaver IV
Potion of Divinity
Recast Delay: 30 minutes
Claimed from Prize: Ping's Protective Potion Pack (grants 5 potions)
Protection of the Dain
Reward from Coldain Ring #10: Ring of Dain Frostreaver IV
Charges: 1
To get a new one, hand your Ring of Dain Frostreaver IV to Dain Frostreaver IV (need Ally faction, or reportingly Warmly, otherwise he will eat your ring).
Shiny Brass Idol
Charges: 1
Drops off rare creatures Hagnis Shralok and Vopuk Shralok in Highpass Hold.
Corrupted Hammer of Consternation
Class: SHD NEC
Procs Harmshield (invulnerability for 18 seconds)
Divine Hammer of Consternation
Class: CLR PAL
Procs Divine Aura (invulnerability for 18 seconds)
Duennan Shielding Ring
Class: MAG
Charges: 1 (rechargeable)
Reward from the Magician Test of Interpretation in Plane of Sky
Flute of the Siren
Class: BRD
Effect; Fermata of Preservation Rk. III (invulnerability for 6 seconds)
Lyssa`s Darkwood Piccolo
Class: BRD
Effect; Fermata of Preservation Rk. III (invulnerability for 6 seconds)