You may be aware that you can see a list of available symbols on your Mac with the Control-Command-Space key combination. By default, you get a nice collection of special characters and emoji. The recent addition of a search bar also helps.

But did you know there are even more symbols? Just click on the circle ellipses in the upper-left portion of the toolbar and then "Customize List…".

That opens up a ton of additional options ranging from dingbats and geometric shapes to international character sets. If you want the African N'Ko character set, you can add it. I have not installed all sets, but I find the technical symbols handy for my MacSparky work. The below screenshots show just a few of to additional character sets I've added. My thanks to reader Jason Cramer for reminding me of this feature.