What can I do to interior brick beside paint?

In my experience, cleaning the brick, painting, removing or covering it with another material such as wood, tile etc. what you decide really depends on what your concern is. For example, is it dirty or covered in soot? This can be cleaned. Painting tends to be a great option if it is just unattractive albeit clean. Some clients opt for adding tile or a wood face, but you will need to consider location of brick and specific needs. If the brick surrounds a fireplace, and materials selected should have heat tolerance for safety. If there is any moisture, that would need to be mitigated as well. Good luck!

Here is an idea I absolutely love, and I wish I had some brick to try it on https://www.bobvila.com/articles/german-smear/

Hello. A Great idea to update brick is to whitewash it. This gives the brick such a great look. Here is an example from the Hometalk website. One of our contributors whitewashed their brick fireplace and it turned out great. Click on the link below and check it out. Good luck!

https://www.hometalk.com/diy/decorate/christmas/whitewashed-brick-fireplace-for-christmas-6103539?r=1

You could built out around it. Many people cover it with a more modern box.

White wash it

try German schmear, saw it done on Fixer Upper and I think it looks great

http://www.serendipityrefined.com/2016/09/tutorial-german-schmear-lime-putty.html

Other than painting or white washing, you could cover with shiplap or wood, or you can choose to tile over. by attaching a plywood cover you can tile over. You can also stucco over it. It all depends on what you are looking for and what your decor is. There are many lightweight stick up tiles that can be used and then taken down later in case of sale.