There's a cliche that fantasy fiction is based almost entirely on the Lord of the Rings. It's not quite true, but like most cliches there's truth in it. Tolkien certainly shaped the space that fantasy lives in, and if he wasn't the only person to do so, he certainly had a lot to do with where the borders lie and how the terrain is set. For some years, of course, after the books became truly huge (the late 60s and into the 70s) it was much more true than it later became, not only because so many aspiring writers had read the books and were imitating them, but because publishers were on the look out for the next epic fantasy in the mold of Tolkien.
If you look closely at almost all fantasy even into the 80s, you'll see a little Tolkien. You'll see plenty even in today's efforts. But there are some series that tread frightfully close to the Lord of the Rings in one way or another, at least to start. Three come to mind for me right away, one of them the starting volume of a still-continuing series; one the first books from a now much-respected author; and one of them nothing but hackwork designed to mimic Tolkien as if it were a clone grown in a lab.
That last is Dennis McKiernan's Iron Tower trilogy. To some degree, it's not his fault that he ended up writing a frightfully precise duplicate of the Lord of the Rings. The story goes that he wrote a sequel to the books and couldn't get the rights to publish them (not a surprise) so his publisher asked him to shift around some details of place and character and then (this is where the problem arises) asked him to write a prequel to his sequel. Because the books he had already were now not anchored to anything, see, so they needed a first series to be based off of. Well, what McKiernan did was buff off the paint of LotR and recreate it, in some cases down to specific sequences (most notably the awful resuse of the Mines of Moria, renamed but very much too-easily identifiable.) He's got little folk (but warlike, so it's different!) and a Dark Lord and elves and dwarves and so on and so forth, in a world clearly meant to be as close to Middle Earth as possible without getting sued. But as I said, it's not really quite the author's fault: he started out to write a sequel, and ended up writing a too-close homage followed by that sequel (and many more books, so he did something right, obviously.) The problem is the Iron Tower books are just unbearable by virtue of being hackishly close to the real deal without in any way being improvements. The writing isn't better--a frequent complaint against Tolkien is that he's not particularly readable; too much exposition, too much dry history--so this could have been a place to take advantage of, but it's not, in this case. I read these books when I was a youth desperately in love with LotR, and even I thought "What is this, and how did it get turned into books?" I haven't read them in years and years, though maybe a decade ago I forced myself through the first book to prove it was as bad as I remembered, as derivative, and it really was.
Better is the Sword of Shannara, founder of a dynasty of books that has climbed into the high 20s as far as total volumes, and which have continued to the present after almost 40 years. Terry Brooks, the author, has ventured very far from the first book, into spaces that are his own (though still within the realm of Tolkien's writing), but Sword of Shannara is a book that lies squarely in LotR-land. With it's motley assortment of men, elves, dwarves and quiet wood dwelling humans (they aren't hobbits, but it's not much of a difference, really), and most especially with Allanon the Druid; with journeys through a Moria/Paths of the Dead composite (what is it with the cavernous city under the mountains that so much captured everyone's attention in Tolkien? It's everywhere, really); with a Dark Lord served by shadowy, flying minions and a magic McGuffin capable of defeating him; it all comes out of Tolkien and though there's a bit more weirdness (post apocalyptic weirdness, mostly) and a bit more active magic (Elfstones!), it's definitely taken from the master. However, it's not completely a copy; it has it's own things going on, and while the writing wasn't the best, it gets better. The next couple of books move into territory that is less Tolkien and more distinctly Terry Brooks: he has weird quests all the time, and heritage is vastly important, and monsters are strange and singular, and his naming conventions become things entirely his own. The series goes on and on, and I've only read maybe ten of them (I act as if that's not a lot) and it gets bogged down in those issues of heritage (how do all these families survive and interact century after century?) but I really remember loving these books greatly as a youth and into my 20s, and when I read Sword of Shannara not too long ago it held up pretty well.
The final one of the three that sprang immediately to my mind is the Fionavar Tapestry by Guy Gavriel Kay. These are books very different from Tolkien in the actual plot and characters: there are women, and a lot of them; the plot is all over the place, and draws in all sorts of elements that Tolkien might have appreciated but probably wouldn't have touched; and they're actively melodramatic and melancholy both, in a way that Tolkien was too fussy and standoffish to really manage. But here's the thing: Kay was an editorial assistant, or a researcher, or something similar (it's hard to pin down exactly) to Christopher Tolkien when the latter was putting together the Silmarillion. And it shows in every single bit of Fionavar. The Lios Alfar are Tolkien Elves of the Silmarillion or Lorien so clearly and obviously; the Riders of Dalrei are a rusticated Rohirrim complete with a great ride to arrive at a battle in the nick of time; Rakoth Maugrim is so entirely Morgoth that it's hard to believe. The style of the books echoes the Silmarillion very strongly; writing beats are hit that no one else really has hit. But it makes perfect sense, as Kay was quiet young when he got caught up in EDITING THE FRICKING SILMARILLION (his late teens!) and how could that not have overwhelmed his writing for a while? His later books are almost all historical fantasies: books set in places that are clearly based on historical lands and places, but twisted around and changed. And so it can be seen that the first "historical" land he decided to tackle was the one he knew best, Middle Earth, and that he did it well. The books are still very good (a little stilted in language, as noted; a little melodramatic) and I've enjoyed reading them again several times. But they solidly inhabit Tolkien's shadow; the fact that they do and still work well shows it's no bad thing to exist in such a space.
I was not immune to the urge; one of the first things I remember writing, when I was a wee grade school boy, involved elves and an old wizard with a beard and a quest to destroy a McGuffin; there was a good wizard who was secretly bad, and there were things that most assuredly weren't orcs except for how they were certainly and definitely orcs. I think that in the main I've left the master behind (for good or for ill) but I inhabited those places happily enough for a good many years. And I still go back to the originals myself, and I still like when it's clear someone else knows them, and has put just a hint of them, into their own books. But like most seasonings, it's best in moderation.