As a wise man once said, welcome to the Elder Scrolls! Our Orcs are elves and our Dwarves are elves! (heck, even our cat-people were once elves)
The Elder Scrolls series definitely started out as more generic and heavily influenced by other fantasy of the time, but has over the years developed into something unique. I don't think it's fair to call anything a "rip-off", it's more so "here's a fantasy universe utilizing pretty standard fantasy things that have existed for decades".
To answer the question of the title directly, the majority of it is what I would definitely call "uniquely Elder Scrolls".
For some of my favourite bits of lore that I find fascinating and pretty unique, I can't say I've come across any other fantasy worlds where one of the major races arose from bioengineering performed by sentient hivemind trees from another world (or even possibly a previous Kalpa, depending on how you want to interpret things), and that said trees can continue to perform bioengineering on individuals when the need arises. I also like that the sun is literally just a hole.