Fixing ceramic tile that have a large ceramic chip off
Patch it with porcelain crack repair. Or for just a color match, and if it's not in a high traffic area, believe it or not I've had a lot of success using crayon: lots of color choices and it's not permanent, so you can try different colors until something works. If you work it into the repair well enough it will stay better than you expect. I did this over a year ago in our living room, it's really hard to see a repair was made there and I haven't had to re-color it.