Let's continue the collection!
Thanks for all the suggestions and ideas in the comments to compendium I, many of the mentioned player types I already had planned, even drawn, many didn't occur to me originally but struck me as types I might even have met myself at tournaments.
Here are three more types of players you might run into; I certainly have. Did you? Please share your sightings of these particular species in the comments with me!

the MANOWAR MAKES ME PLAY BETTER
Having many subspecies largely depending on taste in music, this is a very widespread type. Taste and opinions may vary here, but I am not very fond of opponents who spend their tournament game against me with earphones plugged in, listening to whatever makes them play/concentrate/calm themselves better, as they tend to claim when asked about it.

the CREEPY STARE
Probably a rare species, and I do not hesitate to say, rightfully so. They come in all ages and genders - my first experience with this particularly unnerving type of opponent behavior was in a tournament game against a little boy, who seemed to be trying to strangle me with the sheer force of his stare during the entire game. Sometimes it helps to stare back. When it doesn't, well, there isn't much you can do.

the ARCHITECT
Another common species - also quite variable in reference to both their building skill and imagination. Some settle with repeating simple patterns all over their part of the table, some build entire multi-dimensional structures out of most of their bowls content, sometimes incorporating captured stones into the structure. Either way, they can be annoying sometimes, especially if their hands get shaky during the game progress.