For me, it's StayC and NewJeans. I still can remember the day NWJN's released Attention, i went on YouTube, clicked on the Video and was so amazed by the whole concept. Their music is chill, something you can listen to every time of the day.
I got to know StayC when they released Stereotype on my Birthday. Everything about Stereotype is just so perfect. And about StayC too. I really like their B-Sides, especially Love Fool, Complex and I'll be there (honestly there are so much more I love).
Everything about these two groups feels so nostalgic to me... I can't really describe it but their music is magical.
My Biases: Haerin (NWJNS) and Isa (StayC)