Can anyone recommend books that are NOT series, trilogies or sequels?

Many are stand alone novels, so they would qualify.

The Giver, the Bridge to Teribinthia, the Fault in Our Stars, and Swiss Family Robinson.

There are also books that ARE a series, but it is completely unnecessary to read them in order or the others like Nancy Drew or Encyclopedia Brown

Gone with the Wind. By Margaret Mitchell.

Any of Jane Austen's or the Bronte sisters' novels.

I don't think Jules Verne, Jack London, F. Scott Fitzgerald or Ernest Hemingway wrote sequels. Same with Tolstoy.

The Remains of the Day is a sublime novel and it is not a part of a series. 

By the way, a trilogy IS series so there is no need to say "series, trilogies or sequels." 

By the way, you ought to have written "I ask people not to recommend" rather than "I aske people to not recommend" as you are splitting the infinitive the way you write it and that is incorrect.

You ought not to be accusing others of stupidity until you can demonstrate that you are smarter than everyone else. 

Catcher in the rye

Are you looking for recommendations from a particular genre?

This information will help us to give you books you might be interested in.

I'm not sure what people think. I certainly could give you recommendation of stand-alone novels.

There are some borderline cases. For example, there's The Lord of the Rings which Tolkien intended to be a single novel; ironically, it seems to have established the trilogy as a oft-used form in fantasy fiction - yet the only reason the novel was published in three parts was due to paper shortage in the aftermath of WW2 (the story itself is broken up into 6 "books"). So, one could argue that TLotR is NOT a series.

There are also books that were conceived of as stand-alones and only received sequels much much later. I could see why someone might be tempted to recommend these, too, as they will perfectly stand on their own.

There are also books that are only loosely connected.

An example for both previous scenarios are Ken Follett's Kingsbridge novels. The first one, The Pillars of the Earth, is a fantastic page-turner, a slightly pulpy historical novel that is a pleasure to read. Follett followed it up almost 20 years later with World Without End, another historical novel also set in the fictional town of Kingsbridge but over 150 years later. It's equally readable but you don't need to have read the previous book (nor does the first book leave you with a feeling that you're missing something if you only read that one). The connection is weak - it's mainly the setting and some of the protagonists of WWE are descendants of characters of TPotE. Those readers who know the first Kingsbridge book will get a smile out of these little details but they aren't important at all. There's yet another Kingsbridge book, written 10 years after the second, which is even more removed - 200 years after WWE. I haven't read this one, A Column of Fire, yet but given the large time gap I expect it to be just as much standing alone as the previous books. I could understand why someone would want to recommend one (or several) of these novels because they're just very enjoyable even though one could classify them as a series.

That said, I understand that you are looking for a stand-alones. If you are allergic to series even in the very loose sense as I've described above there's still a myriad of books out there to recommend.

Like I said, if you specify what you're interested in, we might be able to give you just the recommendations you're looking for!   :-)

"a tree grows in brooklyn"  by  betty-smith.

"one flew over the cuckoo's nest"  by  ken-kesey.

"the grapes of wrath"  by  john-steinbeck.

I could recommend dozens of novels that qualify, but you seen to be such a judgmental sourpuss I'll limit myself to one, so I qualify as having replied.

Eifelheim, about alien arrival in Medieval Europe.

Some books are technically in a series, but they also work well as standalones.   Who is the one person who is the constant in all this?  Could it be...  YOU?

Among my fav stand alone SF novels are Evolution, by Stephen Baxter, Aurora by Kim Stanley Robinson and Rejoice by Steven Erikson.

All excellent books, on different SFnal topics and all in print. Enjoy.