Fate: The Winx Saga
I was not yet able to see the second season, as it is not out on german Netflix just yet, I can only say something about the first one. I like it a lot, to be honest. It is sometimes a bit scary, dark and definitively has some tension to it! It does not fail to entertain, despite having only a 5.33/10 on rottentomatoes!
Because there's not much in the Wikipedia article on the plot, I quote it here for simplicity:
Bloom, a fairy with fire powers, enrolls at a magical boarding school in the Otherworld called Alfea College. There, she shares a suite with Stella (a light fairy), Aisha (a water fairy), Terra (an earth fairy), and Musa (a mind fairy). With the help of her four new friends, Bloom starts to learn more about her past. Meanwhile, ancient creatures called the Burned Ones return to the Otherworld and threaten everyone at Alfea.
Because it has some dark scenes, the show might be not appropriate for young children, although it is about fairies and from its description seems to be targeting children!