I'm reading again the bookseries of Knights of Myth Drannor, Ed Greenwood's works.
They remind me the old dear War Wizards of Cormyr and that in the Volo's Guide to Cormyr you can find their magical cloak.
There's the conversion from AD&D 2nd to D&D 5th rules:
War Wizard Cloak
Woundrous Item, very rare (requires attunement), only for wizard
This cloak is black and length to mid-leg for a human male of average height.
It's cut to cover its wearer's breast and arms. Its high collar and hood make it different from normal magical cloaks.
A Purple Dragon is on the hood and on the collar's left side while on the right side there's a white human palm with fingers in circle.
The cloak has the same powers of a ring of warmth and you have immunity from bludgeoning, piercing and slashing damage made by any non-magical weapon ranged attack and by any weapon (made of metal) attack.
On every turn you can use your reaction to cast feather fall.
You can use an action to cast sending (1/day) or dimension door (1/day).
Dimension door spell has a range of 3.000 ft.