I have been modeling for years and I have worked with so many different photographers, however I feel as if I am at a stand still in my modeling career. Does anyone know how you can become a published model without an agent?

Work with a published photographer.

Location is a major factor but try to find photographers who are published.   If you want tear sheets then look around for the urban glamor shooters.   Plenty in the ATL.   Now the bad news.   Without a agent it may be very hard to get published in anything beyond urban magazines.   At 25 I suggest getting a basic acting reel together.   Consider some commercial photos also.

Unless you have a written document in
which the photographer has transferred reproduction rights to you, you will be unable to publish anything, as you don't own the work.

Publishers pass on any material which could lead to copyright infringement litigation.

Unfair as this may seem, it is Federal Law,  only Congress has the authority  to modify it.

As others have suggested, seek out photographers with a proven track record of being published by those magazines which interest you.