You should check out the sets they have at [Juniper Books](https://juniperbooks.com/), lots of sets made to look good together, even have spine art...
You may have luck digging around for modern library or everyman's library editions that have (or had, in the case of modern library) nice standardized cloth bindings. If you're into American Authors, Library of America. You may have luck finding old sets, but they often get split up, and you have to watch ebay or abebooks to put a full set together just watch listings and you'll see which ones come up again and again. That takes work, luck, and often money.
Or you could do it the old fashioned way- those fancy private libraries you see in old mansions with every book matching? People had their books rebound to match their own style. Still possible, just expensive.
Anyway, you may just need to wait on this one until you have an income.
I'm right there with you, bud.
The only way , so far , is to search manually and check the book dimensions before purchase 😫
This question has been asked quite a few times before and I don't think there is any particular website that sells book collections with matching cover and dimension. One way to do it is perhaps to go to the publisher's site itself and search the books by the author. Penguin Books or Vintage are your best bet.
Book Depository often lists separate editions of a book. An email to them with ISBNs of the editions you're after will often give good results.
Go to the publisher's websites. For example, [Penguin Little Black Classics](http://www.littleblackclassics.com/)
Sites like thriftbooks.com can work for buying used books of certain versions and editions. Just look at the list of editions and covers on GoodBooks and you should be good?