oH boy okay I have a few chars to offer!
Ignatius is definitely the friendly sort, and Soft As Heck™. He'd absolutely befriend her, he has a habit of taking in anyone who seems like they need help or a place to be. He's the Alpha of Fyri.
Caelestis is a wildchild that really just enjoys doing whatever she wants to, but if you can get past the rough edges she is a pretty good pal to have. Would absolutely be down for adventures to wherever Ruelle wants to go, and fight off any dangerous creatures they might meet along the way.
Echo also comes to mind, but for the bad experiences idea. She's a coward through and through and really only cares about one wolf. For the most part she's easy enough to get along with - so long as whoever she's interacting with doesn't have anything on them she can try to steal - so I'm sure initially they'd have the potential to be acquaintances or whatever Echo's closest approximation of friends is, however Echo would absolutely abandon her if they ever ran into trouble without a second thought. A little betrayal is always good to get those trust issues kicked up lmao.
More tentative but I have a few more who I don't thread as often.
Rhea could always use friends to get her to come out of her shell a little bit. She's painfully shy much of the time but really a sweet girl, and could use a friend or two outside of Abaven. Totally down for her to go wandering through the east with Ruelle, they can have some fun and be awkward together, maybe run into some trouble and not know how to handle it.
Kvasir is my viking boy. He's also not a terribly social creature, really he prefers to spend most of his time crafting random objects, or searching for inspiration for new things to craft. Not really a good guy or a bad guy, he doesn't necessarily go out of his way to help others or harm them, unless of course they're on the other side of the battlefield during a raid. I haven't had a lot of time to flesh him out so I'm not all too sure how they'd interact. Oh, also he has some pretty nifty horns and thinks he and his brothers are cursed, so that's something.
Czernobog has only recently joined in the viking lifestyle, and he's a lot harder to get along with than Kvasir. Much more self-centered and uncaring when it comes to other wolves, though he does have a softer side that only very rarely comes out. Again, hasn't been played a ton so plot-wise I'm not sure what might come of them meeting.