Path of the World Tree multiclass?

I've been looking into the first character I've ever made, and I've been looking at what to do with him next. Initially back in 3.5e, he as a soulknife dragonborn, but I was dumb and plqyed him like a barbarian, while not even knowing soulknife was just part of the rogue class. Canonically that party delved into hell where one of them became the ruler, and my dragonborn evolved into a recurring character in future campaigns as a paladin barbarian in 5e, but for more campaign shenanigans he has returned to the overworld, and I dont know what to do with him now

I like world tree for his barbarian subclass to give off a more wizened viewpoint for him, but I still want to multiclass him with something, and I want to avoid anything that involves striking a deal or worshipping a god. What classes might fit? I was considering ranger

And before you say anything, I dont like to reflavor as I prefer mechanical creativity, as does our dm, and it doesnt have to be perfectly optimal of a combination. I'll optimize the combination I find the best thematically fitting for his character. Thank you!