The answer is, if you are creating fan art whether for profit or not, any copyrighted character or use of trademark in a description or title without prior written consent from the copyright owner, then selling fan art is illegal but making fan art is not illegal.
Is it OK to sell fan art?
Technically speaking, theres nothing illegal in the US about making and selling fan art because copyright isnt enforced criminally. If you dont want that threat hanging over your shoulder, your best option is to try to get permission from the copyright owner to make and sell your fan art.
Is it legal to sell fan art at conventions?
Its not legal to sell fan art at conventions if you havent acquired permission to do so from the copyright holder. The copyright holder can give you the right to sell fan art based on intellectual property created before. With the copyright holders permission, you are able to sell fan art at conventions.
Is it illegal to sell fan art on Etsy?
You have the exclusive right to use it unless or until you give other people permission to use it. And further, you control how they use it. For example, you can stipulate whether its strictly for personal use, or commercial. That is, whether they can sell what they make with it.
Can I sell art of a celebrity?
You can sell a fine art painting of a celebrity as long as it is a transformative work of art. This means it needs to be artistic in nature, not just a faithful likeness. The painting cannot copy an existing work of art (including a photo), and cannot interfere with a celebritys “right of publicity”.