There are a couple different spells and abilities that give additional illusory duplicates
Cleric of the Trickery Domain
The Trickery Domain offers an additional Channel Divinity option to Invoke Duplicity:
As an action, you create a perfect illusion of yourself that lasts for 1 minute, or until you lose your concentration (as if you were concentrating on a spell).
At a later level, you can get more duplicates:
At 17th level, you can create up to four duplicates of yourself, instead of one, when you use Invoke Duplicity.
Wizard of the School of Illusion
Illusionists get the ability Illusory Self at level 10:
you can create an illusory duplicate of yourself as an instant, almost instinctual reaction to danger. When a creature makes an attack roll against you, you can use your reaction to interpose the illusory duplicate between the attacker and yourself. The attack automatically misses you, then the illusion dissipates.
Fighter of the Echo Knight Archetype
Explorer’s Guide to Wildemount introduced a new fighter archetype called the Echo Knight which has the ability Manifest Echo:
You can use a bonus action to magically manifest an echo of yourself in an unoccupied space you can see within 15 feet of you. This echo is a magical, translucent, gray image of you that lasts until it is destroyed, until you dismiss it as a bonus action, until you manifest another echo, or until you’re incapacitated.
At level 18, you can get more duplicates:
You can use a bonus action to create two echoes with your Manifest Echo feature, and these echoes can coexist.
While it doesn’t serve any additional purpose other than the illusion itself, major image can create an illusory copy of yourself:
You create the image of an object, a creature, or some other visible phenomenon that is no larger than a 20-foot cube. The image appears at a spot that you can see within range and lasts for the duration. It seems completely real, including sounds, smells, and temperature appropriate to the thing depicted.