~ My Question
Is it fine to use assets that belong to another group, but was found through Free Models or retrieved from peers. The sources are unknown, but what do you think I can do? Can I get banned? The asset I’m mainly referring towards are Morphs.
Thanks! 
Hmm. If what you’re using is from free models and they don’t ask you to give credit, you should be fine. Certain free models like Luxiar’s elevators demand credit if you rebrand the elevators though, so do check the free models for a ‘Read me’ kind of script. If you’re finding it from a group, then they could tell you to give credit.
If they are free models then you can use them. I used to use free models with no attribution (credit) and I never got in trouble. However, it is not worthy that many players do not like free models and it may cause toxicity.
Yes I’m well aware of that, that solves my main question. However for future references, what if it was not retrieved from the toolbox?
Then the creator of the free model should give prior notice about giving credit. If they don’t, it likely means they’ve glued their logo to the free model. They would also have strict regulations and even ‘Terms of Conditions’, like CheckMeIn.
Thanks, that supports my main question but not quite my second.
Refraining my second question: What if the asset was retrieved from somewhere else that’s not the Toolbox, whether it’s a website, Discord, etc. Is the asset still vial?
You’d have to ask the owner of that asset about it.
What if you cannot find the owner of it?
(I’m not sure how, but it’s a possibility.)
Then I wouldn’t suggest you to use it. Who knows, it could be a leaked model from another game. How would you find an asset without knowing the owner anyway? If you don’t know the owner, chances are the person that sent it to you knows the owner, just trace it back.
I was looking this on a perspective of auctioning assets.
Are you auctioning the assets or are you buying the assets from an auction? If you’re buying the assets from an auction and the auctioneer doesn’t tell you who the owner is, then you should ask them yourself. If they’re not willing to tell you something fishy is going on and you shouldn’t use that asset.
It feels like once a week someone is asking a question like this, and the answer is the same: If you didn’t make it yourself, contract it to someone else, or get explicit permission to use it… don’t use it.
Using assets from another game that was uploaded as a free model doesn’t give you the right to use them automatically. The person uploading could have stolen the asset themselves, and you can’t just say you didn’t know, because it’s your responsibility to find out.
Will you get into trouble? Probably not. Is it worth risking the copyright strike on your game? No.
Also
The sources aren’t unknown if you said the assets belong to another group. If you see those assets as free models by someone other than the owner, there’s a pretty good chance those assets were stolen.
If you can’t find the original owner, that means you didn’t get permission.
Sorry that didn’t clear up, I meant that they may belong to another group but I have no clue which group.
EDIT: But I get I need to take the time to find out which.