Fictional Starfleet uniform

A fictional Starfleet uniform is a uniform created by a person, culture, or civilization for a work of fiction, and is usually based on real Starfleet uniforms.

Examples include the 2367 illusion created by Barash and the 31st century The Voyager Encounter exhibit at the Kyrian Museum of Heritage. 

Barash's illusion
In 2367, Barash trapped Commander William T. Riker in a holographic illusion set in the year 2383. 

Duty uniform
Fictional duty uniforms in this era were very similar to the ones worn in 2367. 

Admiral service uniform
A new Admiral's uniform was seen worn by the illusory Jean-Luc Picard. 

Rank insignia
All illusory uniforms lacked the rank insignia on the collar present in the 2367 uniforms. Instead rank was distinguished by different sets of bars behind one's combadge. 

Dala, Mobar and Zar
In 2376, Dala and Mobar impersonated Captain Kathryn Janeway and Lieutenant Commander Tuvok of the USS Voyager. Their uniforms were very similar to the 2371 uniforms worn by the Voyager crew. One notable exception was the overshirt collar, which was wider than on Starfleet uniforms. Also notable were their oversized rank insignia and communicator pins. 

The Voyager Encounter
In the 31st century, acting on incomplete information, the Kyrian Museum of Heritage attempted to recreate what they deemed the Warship Voyager and their acts of plunder in 2374. The duty uniforms created were slightly different than the ones present in the 2371 version worn by the USS Voyager crew. These uniforms lacked rank insignia and a combadge, and had a black undershirt, as well as black gloves. Corrections were made later by the EMH backup module.