Wand of Imperceptibility, self-only, 8-second cast, outdated.
Ring of the Ancients, 0.5-second cast, easy quest reward, but only during Anniversary season. Best option.
Earring of Diminutiveness, 0.3-second cast, rare instance zone drop.
Humanoid Reductionizer, 0.5-second cast, rare instance zone drop.
Bracelet of the Shadow Hive, 1.0-second cast, rare drop from raid mob.
Shimmering Bauble of Trickery, 1.0-second cast, rare drop from raid mob.
Philter of the Ant, 1.5-second cast, crafted alchemy, expendable potion.
Anizok's Minimizing Device, 8-second cast, crafted tinkering, must be recharged.