In the Netflix series, a few things clear up when you realize the raven is a huge Thunderbird.
It's why he didn't recognize a cat as a threat to him even though he knew they were dangerous.
It might be why he's bad at names. He's never had to remember one.
It's why he has teeth inside his beak. He can catch food in a way most birds can't.
On the subject of the raven, the art style keeps you from recognizing him as the bird from the first episode: He's more detailed there, and he's rarely facing the direction he does when he's walking.
On the beginning of Chapter 2 of the Netflix series, Hilda goes to sleep when the sun is setting outside, and the clock showing that it's almost 10 o'clock. This is because the show was inspired by Scandinavia, a place where the sun can set at 10-11pm, and rise at 2-3am in winter.
Frida being a witch is kind of obvious when you think about it while Hilda can perform magic she performed the spell incorrectly and Frida was chosen by the Mara to become one of them for some reason. Which is now revealed because she has a natural talent for being a witch.
Bells seem to be greatly upsetting for all manner of magical creatures. From trolls to elves, and even the woffs. In a lot of classical traditions, bells have been used to frighten or ward off the fae from humankind. Though it seems for some of them, the trolls for example, the ringing seems to only make them irritated.
The elf contracts. In many traditions, different varieties of fae have been known to engage in very specific verbal agreements with humans in order to make contracts or exchanges. It makes sense then that the elves, invisible small creatures, are so preoccupied with keeping contracts in order.
In "The Yule Lads" Kertasníkir tries eating a candle and, disgusted, tells Hilda that his candle "might have gone bad". Candles used to be made of beef fat (tallow), and thus perfectly edible; no wonder he didn't like a "modern" wax candle.
Chapter 6 was when the first Marra 'met' Frida. Is she the one who suggested that Frida join their ranks and got Kelly to pressure her into the group?
Back in the first season it was said that ghosts are more likely to fixate on items they owned than people they loved because their loved ones will die and join them eventually. But the Draugen were separated from their friends and families who died on land for centuries, what could that have been like?
Lloyd was grabbed by the beast of the Void of No Return and is not seen again. It's pretty obvious he died and most likely was eaten. And no-one cares.
The vikings treat the revelation that Sigurd has basically trapped them in a pointless eternal fight for hundreds of years as a good joke, but think about the implications; the potion Sigurd uses to revive them also wipes their recent memories, so from the vikings point of view they have been fighting over the medallion for maybe a couple of days, while in fact it was a couple of centuries. Their home and all their loved ones they had there are long gone, and the world has changed beyond recognition.
Victoria Van Gale used black magic to make her own "nisse". One made of plants and debris and...a skull?! Who's skull is that?! It's small and very obviously humanoid. She made an undead homunculi/copy of a fae creature. That was reduced to a chattering skull at the end of it's tale. WHERE DID THAT SKULL COME FROM?! HOW MANY OTHER REMAINS DID SHE DISTURB?!
Wasn't it fake and made up of other stuff?
At the climax of "The Fifty Year Night", Hilda witnesses her future self get devoured by the Time Worm. While Hilda doesn't seem too worried about it, there is the uncertain implications that this might be her eventual fate.
By the end of the episode, the alternate Mr. Ostenfeld and Tildy both sacrificed themselves to save Prime Hilda and Tildy from the Time Worm by ripping the original magazine in half. Now considering that those versions of Mr. Ostenfeld and Tidly were married, that means they probably had children. Does that mean that their offspring were eaten by the Time Worm as well?