I’d probably best to send this again, maybe more focused on certain characters at a later date. I’m currently doing a rewatch of the whole series (I’ve just finished the movie atm) so that should help but off the top of my head here’s a few since S3 is somewhat fresh.
Due to Hilda’s fairy background, Frida is able to siphon some essence and cast certain spells that require it (it’s like donating blood…without the blood, it’s safe). This however led Kaisa to inquire on how she was able to cast those old spells. Frida spilled the beans on Hilda and Johanna being part fairy and Kaisa wondered if getting essence from a half-fairy would be more potent and so she and Frida went to Hilda’s place. When Kaisa saw Johanna it was love-at-first-sight and she completely forgot about y she came over at first. Johanna was hesitant on what Kaisa wanted but offered to go get some tea at a cafe sometime and discuss it. This led to their first date, then their second and so on. Eventually Hilda got a witch step-mom.
After her time as a Troll, Hilda developed a slight fear of bells. While not as painful as it was when she was a troll but she can’t stand the noise.
David became an entomologist due to his strange magnetism of insects and general fascination. Louise helps take pictures of whatever bug he’s studying for his research papers. The most annoying bug he’s dealt with was the Mothman during a research trip to America alongside Hilda.
Louise became a photographer, she helps David and Hilda with their research but she is also an award winning photographer.
Alfur with a continued note-taking partnership with Adeline eventually after a few years presented her with “Engagement to be Married” papers and she signed gleefully. After a few months of planning and revisions, the wedding was both tiny and had all of the proper paperwork filed in order (Bartell was Alfur’s best elf).
Eugene eventually made it to the sea but after he saw the Trolburg harbor he makes it a point to come by and try out new material with the sailors. This annoys the freaky friends since they still don’t find him funny but the sailors do.
Frida was given a witch’s cloak as a gift from Tilde. Similar to the one Kaisa wears. It was made from Witches’ Wool, an ancient recipe lost to all but a few witches in that dimension. She explained its origins being from a demon realm where witches live on a Titan’s rotting corpse but all portals there have dryed up over the centuries.
Deputy (now Chief) Gerda while a more “by the books” chief of the safety patrol, was more understanding towards magical creatures and issues and preferred to listen first before making decisions. This has led to a number of new rules within Trolburg to accommodate its more mystical citizens as she worked to get humans more comfortable with their strange neighbors.
Wood Man slowly rebuilt the cabin Hilda and her mom lived in. He says it’s so he can have a second home away from home but secretly it’s so his old neighbors would visit more often, which they do.
Aunt Astrid helped teach Johanna and Hilda a bit of fairy magic. While it’s not as strong as it was back at fairy country and because they’re part human but there’s still a few spells that they can perform, mostly minor things (think Cantrips in D&D)
Johanna and Astrid made Hilda a new sweater with fairy magic and charms woven into it. She wears it always (washing it often of course)
That’s just a few off the top of my head atm. Hopefully after rewatching S3 I can think of some more
