Hello,

I'm trying to create a magic item for one of my PCs that would effectively give them the Rage feature from the Barbarian class. I was trying to tie the feature to a weapon, but didn't see anyway to implement this.

Has anyone done anything similar? Is there an easy way for me to add another classes feature like Rage either to a weapon/item/feat that I can assign to another class? Or is this not possible today?

The character sheet doesn't account for temporary stats like rage, so a fair number of people playing barbs have made magic items that they can equip and unequip to mirror rage. It doesn't work perfectly, but you should be able to get most of what you need. I ended up splitting out the rage damage into a spell that functions sort of like booming blade, so that it could level up in damage without me having to change it. Then I granted the spell via the magic item, which also granted the advantage on STR checks and saves and resistance. You can also give an item charges (to make sure it's only used a certain number of times per day). You might run into issues with attunement, though, because a weapon that grants stuff like this ought to require attunement, but if the effects need to go away but you need to keep the attunement saved for this magic item, that might be a little trickier.

Gotcha. Do you know if it's possible to just add the Rage feature to their Features & Traits page with a feat or magic item? It doesn't appear to be supported unless you actually have levels in the Barbarian class? I'm not too worried about making sure that all the stats apply correctly from Rage, was mostly trying to get the Rage feature to show in the PCs Features & Traits page. 

There's no way to assign a class feature as a feat or an item. We can't edit classes, so there isn't any access to anything that only exists as a class feature. Plus, as I said, the character sheet doesn't do temporary features at all yet, so it doesn't even really do rage for Barbarians, either. It's just text.