The Astral Projection spell allows you to travel to the Astral Plane, where you are invulnerable… unless someone cuts your silver cord. Some effects that allow this are the githyanki knight's silver longsword, and the astral dreadnought's Sever Silver Cord trait, both of which allow them to cut silver cords on a crit. However, Adamantine Armor can mitigate this.
What other ways can a character traveling using the Astral Projection spell have their cord cut?
I'm looking for a list of official monsters and other hazards that can sever cords in order to build a character who is as invincible as possible on the Astral Plane. (I already am aware that you need to make sure nobody can find your body on the Material Plane.)
Best Answer
All known methods of severing a silvery cord involve a critical hit.
Besides the githyanki knight and the astral dreadnaught, the githyanki supreme commander also possesses the ability to sever a silvery cord on a critical hit.
Finally, Mordenkainen's Tome of Foes contains a writeup for a greater silver sword magic item, which can be attuned to and used by any "creature that has psionic ability." Any creature using this sword can sever a silvery cord on a critical hit.
Addendum: There is a sentence in the DMG that states that "Only a few things can sever a traveler's silver cord, the most common being a psychic wind (described below)." But that description does not mention cord-severing at all. So it is possible that a DM reads that sentence and comes up with a way for a silvery cord to be severed by a psychic wind in a way that does not involve a critical hit. Thank you to Nobody the Hobgoblin for pointing this out.