I don't often need HTML glyphs apart from the usual suspects (& for &, < for <, etc.) but when I need to find a specific one, I always waste time finding it again.
I found a good reference which lists all the glyphs. However it is slow to load all the glyphs and the default font size is too slow to see the details of the glyphs. I need to increase the text size (and reload the whole page) several times to have a better look at the glyphs, making it really slow.
I finally decided to have my own cheatsheet to reference the glyphs I sometimes need (and some I may use one day...).
I will never waste time again to find the Command key ⌘ (⌘).