Staff of the Weaver Arcane

Staff, legendary (requires attunement by a sorcerer or wizard)

This staff has a series of narrow openings at its top through which threads of magic visibly flow. It can be wielded as a magic quarterstaff that grants a +1 bonus to attack and damage rolls made with it. While holding the staff, you also gain a +1 bonus to your spell save DC, spell attack bonus, AC, and any saving throw you make.

When you cast a spell of 3rd level or higher using a spell slot and are holding the staff, threads of lingering energy wrap around the staff. The number of threads is equal to the level of the expended spell slot divided by 3 (rounded down). You can have up to 3 threads at a time, which remain until they're expended or until you finish a long rest. Until then, whenever you would expend a spell slot while holding the staff, you can instead expend a number of threads from the staff equal to the spell's level; if the spell has a casting time of 1 action, you can cast it using a bonus action instead. Regardless, treat a spell cast in this way as though it were cast with a spell slot, except that it doesn't generate any threads.

In addition, if you hit a target with the staff, it deals an extra 1d6 force damage for each thread it has.

Under the hands of a master weaver, a tapestry becomes so fine that one may forget it is merely a thing of thread. Even so, such work can come undone with a single pull.
But thread can be sewn anew, and tapestries remade.
This is what most spellcrafters forget, or perhaps never thought to know. Our magic is a complex web of threads pulled taut; to be wasteful with them would be to burn our tapestries with every incantation.
—Excerpt from Treatise of the Weaver Arcane, by Oscar Rove