I tried using the various search functions this site offers but somehow I'm unable to get the hang of it... What I want- All light novels/web novels having only 1 volume or chapters around 20. It would be very helpful if someone could set up the filtered search and provide me a link of it. Thank you.
https://www.novelupdates.com/series-finder/?sf=1&rl=20&mrl=max&cp=yes&sort=srate&order=desc Or you can always use the Short Story tag too (though it has less results) https://www.novelupdates.com/stag/short-story/
could also look for the one-shot tag edit: also while its not one volume The Lazy King is a great read which is complete and relatively short compared to most other novels at a whopping 16 chapters
In a World Without Life Manuscript Screening Boy and Manuscript Submitting Girl Three Days of Happiness I Want to Eat Your Pancreas Kuzu to Kinka no Qualidea Love Me Again Mimizuku to Yoru no Ou
I know that this isn't what you asked for (as they are neither Light Novels nor Web Novels), but David Gemmell's books, which are English Originals, are all capable of standing alone, from the wide array that I have read. They do have series, a wider world and can even follow a single individual, but each individual book can also be read in any order, or simply on their own, and you will still gain everything from them that you would when reading them in series. Hell, the first book to be written in his Drenai Series (I just found out) has one of the main characters of a significant part of the rest of the series acting as a secondary character, and I would have sworn if I had just read the books that it was written with all the information about that character from earlier in the timeline, and later written books, known to the author and potentially available to the reader.