Seasonal costumes?

As an avid costume collector, I'm a bit disappointed by the lack of comestics and costumes available in the game so far. I've watched Sywo's video on KR cash shop costumes and they're pretty much the same as we have right now.

However I also watched some KR videos and people wore more casual outfits, like a hoodie, a frog suit and so on. Are those seasonal cash shop costumes or are they obtainable only during specific events?