To recap from the other thread: for a long time, I used to organise macro groups by using prefixes, but I recently stopped doing so because (1) it’s handy to be able to select a macro group (or at least land in its vicinity) by typing its first few letters when the focus is on the Groups list; (2) the icons that I use (sparingly) after some kinds of macro groups gave me enough context.
The advantage of point 1 is not that significant, especially if one uses @Nige_S’s macro Go to macro group*, which will find any macro group easily.
On point 2: the main icons (illustrative characters) that I use as suffixes are 
and 
to indicate whether a macro group is active globally or is restricted to one or more applications. Also, as I’ve mentioned previously, I use 𝓢 to indicate a group of subroutines.
The choice of symbol for applications is not one that I am happy with. I understand that 申 in Japanese refers to a job application rather than a program! However, to date, I have failed to find a replacement that I find thematically and visually acceptable. It is odd that a search of Unicode character sets plus Apple’s “SF Symbols” did not yield anything obviously suitable for the concept of “program”… so perhaps I have missed something!
For my use case, I have not found it useful to segregate my macros from those of other KM users. The vast majority of my macros are ones that I have made, but for other people’s work, I just like to make sure that each macro contains a note of attribution; I will often add a Comment action that contains the URL of the relevant forum page.
* I made one tiny tweak to my copy of the macro; I turned off the “Notify on failure” option for the Prompt with list action, so that escaping from the list by pressing ⎋ would not display an error notification.