An entry in Fortnightly Topic Challenge #42: Wordless Connecting Walls
Knockoff Gladys was quite happy about how their last puzzle was received. So happy, in fact, that I found a new note waiting for me today. They may have been, um, slightly buzzed while writing it.
Hey, bobble!
Seems you were right - those PSE folks do have very large brains. Big brains. Very big brains. Did you know that brains, they think for us? And their brains, their brains solved my other puzzle! So I made another one. Split the flags into four groups of four - you know, the number 4, it's 2 times 2, isn't that coooooool - find a flag that fits in all the groups, blah blah blah. Let’s see if your friends can find the patterns, the commonalities, the groups, the… hoo, boy, this stuff is great, y'all!
-K. G.
Seems like you need to find some patterns in these flags. Also I might need to get K. G. some help...