I’ve read a good portion of the vampire stories published prior to 1900. Here are what I consider to be the essential ones. You can get all of them for free or very cheap as ebooks.
Any collection of vampire stories must start with Dracula. Bram Stoker’s novel deserves its status as a classic and, unlike a good deal of 19th century literature, is perfectly readable to modern eyes. If you’ve never read it, Dracula is one you shouldn’t skip.
If Stoker is the father of vampire literature, Lord Byron is its grandfather. His 1813 poem, The Giaour, contains one of the first references to vampires in the English language. Lines 757–768:
But first, on earth as vampire sent,
Thy corse shall from its tomb be rent:
Then ghastly haunt thy native place,
And suck the blood of all thy race;
There from thy daughter, sister, wife,
At midnight drain the stream of life;
Yet loathe the banquet which perforce
Must feed thy livid living corse:
Thy victims ere they yet expire
Shall know the demon for their sire,
As cursing thee, thou cursing them,
Thy flowers are withered on the stem.
In the summer of 1816, Byron, Mary Shelley, Percy Bysshe Shelley, and John William Polidori spent a weekend together in Switzerland where they engaged in a “ghost writing” contest. From that weekend, Shelley produced Frankenstein, and Byron wrote A Fragment of A Novel, an early take on a vampire story.
📕A Fragment: Read online here.
Inspired by Byron’s story, Polidori wrote The Vampyre; A Tale, in which our protagonist Aubrey comes to meet Lord Ruthven and discovers him to be a fiend who preys upon Europe’s socialites.
The next major work is probably the 1845–1847 penny dreadful Varney the Vampire by James Malcolm Rymer and Thomas Peckett Prest. It’s fun and was definitely an influence on Stoker, but I wouldn’t call it essential reading.
A direct precursor to Dracula comes with Joseph Sheridan Le Fanu’s 1871–1872 serial Carmilla. It features/establishes the lesbian vampire and has a vampire hunter who clearly presages Van Helsing.
Last and least, there’s my own book, 📕Wallachia, which is set 77 years before the events of Dracula. I put out new chapters every few weeks for free via an iOS app I designed, or you can listen to the audiobooks as a podcast, or get the prelude, Flowers of Transylvania, on Kindle or Apple Books.
† Amazon’s copy of In a Glass Darkly is split into three parts, the third of which has Carmilla. For 98¢ you can get the whole collection for Kindle, which has a few other good ghost stories. The Apple Books and Project Gutenberg collections are complete and free.