In other patching jobs, I used leftover tile grout to patch some holes. I had so much left and didn't want to waste it. The problem is the color is beige (see below) and the several beige patches on the wall looked so atrocious!
So how do you recolor the patch job (sealant or grout or whatever) so it matches the surrounding masonry? Color it with concrete! To do that, mix just a little cement and sand with a ratio of 1:3. Overwater it so it's syrupy as shown below.
Dip an old used paintbrush into the mortar mixture and "paint" it on the patch. You could use less sand if the mixture is too lumpy. I liked it this way though because I was able to cover some more small holes in the wall with the syrupy mortar.
Here's how the "paint job" looks like after it has set and dried.
Notice how the color now cleanly blends with the surrounding color of the concrete wall.