For small jobs and if you're a do-it-yourselfer, there is TEC Grout Recolor. I had white subway tile backsplash put in my kitchen about 7 years ago, then 5 years ago I had the kitchen refaced in white cabinets. The backspash seemed to blend in so much, that it no longer stood out. I bought this product at Lowes, they do not stock it in the stores, but you can order from their website and receive it in less than a week for about $12.
It is a little messy, I found the best method was don't try and stay in the lines but immediately wipe the access off with a wet sponge or rag. It really made the backsplash pop and I was glad I did it. I used just a gray color instead of a blue or some other color.
https://www.lowes.com/pd/TEC-Skill-S...itive/50334043
