You can paint it a color, wallpaper it. I do both all the time looks awesome. You can add trim to make patterns on wall like squares or diamonds. Add bead board.
With a VERY ugly ceiling problem I had with a little house remodel I ended up covering up with the new styrofoam ceiling tiles. They're not really cheap but they're incredibly easy to put up and they're paintable and they look nice too! https://www.hometalk.com/29254181/covering-up-a-very-ugly-ceiling-with-styrofoam-ceiling-tiles
Besides the obvious like paint there are ceiling tiles. Plastic, metal and even paper wall paper like that you can paint or leave alone.
Ship lap or wood on the ceiling is an idea.
I always suggest to think of your theme and go from there.
Think about the style of your home. Wood planks work well and can be painted or stained to fit your decor.