You can follow this LINK to find a whole bunch of free content for UE4. A lot of the links have been listed on the UE 4 forum, but sometimes those are not up to date, this one seems to be having regular updates.
It also has links to other UE4 content that is not listed in the UE4 forum that are for sale on places such as Gumroad and some "creator" sites.
So go check it out and let me know what you think!
Also I will pin this thread to the top, if you all find something that isn't listed in the above site or maybe you know of another one that has links that may not be listed above, please let me know!