Hi Venu,
Thanks for that link, but it only describes the 1-1 and 1-N icons, which I mention in my original question are the more common ones and therefore, everyone knows what they mean. I'm looking for a full list of all the different icons, as David Garcia provided in an earlier response.

As you can see, there are other icons that exist, like the grey 1-1 icon, and I can't find any description of what they mean. I get asked this question by learners all the time so I'm hoping someone has the answer and we can create a reference document with all their description.