What about Merida and Astrid?
or maybe not as ship, maybe as friendship?
YES YES YES I really adore Merstrid as a BroTP!!! Highkey I think they'd be best friends if they ever met. Honestly I see them being closer friends than Merida and Rapunzel (steaming hot take, I know lol)--like Rapunzel and Merida would be close for sure, but Astrid and Merida are both so stubborn and determined and badass and have a TON in common, and I can see them being extremely ride-or-die for each other. Absolute BFFLs and you can't change my mind! Lowkey Merida might have to play mediator if Rapunzel and Astrid ever butted heads (which I kinda think they would lol).
I DO think they're a bit too similar for them to last as a romantic pairing, BUT I actually kind of love the idea of them being each other's Gay Awakening and maybe experimenting together a little??? Like I can see them being childhood best friends and then once they realize they're both gay they're like "well...should we date or something???" They're kinda into each other, but they're not sure if their affections are platonic or romantic because they've been friends for so long??? So it's hard to tell??? Maybe they date for a bit and it doesn't work out, but I like to think there wouldn't be any hard feelings and they would agree to always stay best friends! Fr this is such an underrated dynamic, and one of my top BroTPs in the fandom for sure. Honestly the only other pair I BroTP this hard would be Rapunzel/Anna!
Back in ye olden days of the fandom I saw a lot of takes that these two would be rivals over Hiccup, or just in general, but that just seems...so dumb??? Like boy are so low on BOTH their priority lists lmao, they ain't gonna waste energy fighting over one. And I can't see them just hating each other for no reason (unless they bought into the Scots/Vikings rivalry, which I sorta doubt they would because they both seem smarter than "hate this person from a rival tribe because they're from a rival tribe" lol)--like they both value strength and cunning and kicking ass with their weapons and smashing the patriarchy and all that good stuff, so yeah, they'd get along FANTASTIC. In this house Astrid and Merida are besties!!!
Also Anon I think it would please you to know that once in a Hiccanna fic I wrote a while back, I got so annoyed with the Hiccstrid/Mericcup shipping wars I saw going on at the time that I paired Astrid and Merida up in the story solely out of spite. It was the pettiest shit but I still can't help but be proud TBH XD