Are there magic items that generate Darkness as the spell?

[Cicciograna]

As per the title. I'm about to gain my 2nd level in Warlock, and with it the Devil's Eyes incantation: spell slots come at a premium, so is there anything with which I can reliably cast multiple times Darkness?

[Unoriginal]

A Wand of Darkness?

[ProsecutorGodot]

Reliably? No. The only printed item that can cast Darkness is a Wand of Wonder, and only 5% of the time.

You always have the option of asking your DM to help you create such an item. There's an item called Galder's Bubble Pipe in the Extra Life Lost Laboratory of Kwalish adventure:

Rare, Requires Attunement
This finely carved pipe blows odorless bubbles instead of smoke when used. The pipe has 3 charges, and it regains all spent charges daily at dawn. While you hold the pipe, you can expend charges to gain access to the following properties:

You can cast fog cloud as an action (1 charge).
You can cast misty step as a bonus action (2 charges).
You can summon a steam mephit as an action (3 charges). The mephit is friendly to you, obeys your verbal commands, and acts on its own turn in the initiative order. It disappears in a harmless puff of steam after 1 minute or if it ends its turn more than 60 feet from the pipe.
It could pretty easily be reworked into a darkness emitting smoking pipe, although for as useful as it would be casting Darkness instead of Fog Cloud, I'd probably up it's rarity to "Very Rare"

[Damon_Tor]

Ring of Spell Storing. A godsend for Warlocks.

[Gastronomie]

Ring of Spell Storing. A godsend for Warlocks.This and Ioun Stone (rare).

If your DM is willing a Wand of Darkness could work, but that's a completely different matter.