The main archives with special collections of books, manuscripts, butterflies, and memorabilia related to Vladimir Nabokov, his family and his wider milieu. If you know of others, or have more detail, please add!
Note that some of the material is directly available digitally.
American Museum of Natural History. What remains of Nabokov's butterfly collections is distributed among the American Museum of Natural History in New York, the museums of Harvard and Cornell universities, the Zoological Museum in Lausanne, and the Nabokov Museum in St. Petersburg. A sizable sample of Nabokov's butterflies can be seen here. Please note that the video is navigable. (ZK)
Bryn Mawr Library, Katharine White Collection. White's New Yorker letters to and from Vladimir and some to and from Vera. Some letters address Lolita. (ZK)
Columbia University Library, Bakhmeteff Archive. Nabokov's correspondence with Vladimir Mikhailovich Zenzinov (1900-1953), Chekhov Publishing House, 1951-1958, Vladimir Feofilovich Zeeler (1870-1950), Roman Grynberg (1930-1970), Abram Saulovich Kagan (1909-1952), Mark Aleksandrovich Aldanov (1926-1957), Sofiia Vladimirovna Panina (1900-1956), Mstislav Valerianovich Dobuzhinskii (1910-1957), Alexis Goldenweiser (1900-1974), Avrahm Yarmolinsky (1918-1967), Michail Mikhailovhich Karpovich (1900-1959), George Vernadsky (1887-1973), Sergei Viktorovich Potresov (1906-1963), Manfred Kridl (1925-1974), Pavel Nikolaevich Miliukov (1879-1970), Evgenii Vasil'evich Sablin (1886-1949), Jane Howard (1930-1996). (ZK)
Cornell University Lepidoptera Collection. See note for the American Museum of Natural History.
Cornell University Library, Vladimir and Véra Nabokov Publishing Correspondence,1945-1977. "Approximately 100 original letters and telegrams between Vladimir Nabokov and Doussia Ergaz and Marie Schébéko, his agents at Bureau Litteraire D. Clairouin, discussing in detail rights and translations, Lolita, and other professional matters; approximately 325 items between Maurice Girodias at The Olympia Press and Ergaz and Schébéko, discussing publication of Lolita, in English and in translations; the French ban on the novel; and subjects related to the early life of the book; approximately 2000 items capturing three decades of correspondence between Véra and those involved with the publication of Nabokov's works. Including about 500 typed letters signed by Véra Nabokov to Ergaz and Schébéko as well as carbons of their replies, and related correspondence and documents." (ZK)
Houghton Library. The link provides a guide to the recently donated collection of Vladimir Nabokov family papers, also available here as a pdf. Fans of model trains should enjoy Boxes 1-10. Collection includes 13 letters from Vladimir Dmitrievich Nabokov to Vladimir, over 100 letters from Nabokov's mother Elena Ivanovna from the mid 1920s to her death in 1939 to Vladimir and Vera and over 200 letters from Vladimir and Vera to their son Dmitri. There are also letters to Dmitri from his school and college friends between 1947 and 1957. Special restrictions apply to the contents of Dmitri' s laptops. Files from the laptops are available in digital format, but require special arrangements with Houghton curatorial staff for viewing (see finding aid for the collection). The 107 floppy disks that accompanied those laptops are not yet available, we expect them to be processed in the late Spring of 2019.
Museum of Comparative Zoology. Nabokov's butterfly collections from 1940 to 1948. (ZK)
Lausanne, Musée cantonal de zoologie. Houses VN's European butterfly catches from 1960 to his death.
Library of Congress. Vladimir Vladimirovich Nabokov papers, 1918-1974. The second most substantial collection of VN papers, donated 1959-1964 to provide tax relief from the sudden increase in VN's income post-Lolita. Quick description: 7,000 items, including 13 microfilm reels. The linked PDF catalog provides the full details. Zinaida Shakovskoy papers, including over 50 letters from VN. Bollingen Foundation Archive, with rich correspondence between VN and the publishers of his Eugene Onegin translation and commentary. (ZK)
New York Public Library, Henry W. and Albert A. Berg Collection. The most substantial collection of Nabokov papers: those remaining in VN's archive, and Véra Nabokov's, after he donated some of his early Russian materials to the Library of Congress between 1959 and 1964 for tax relief from his post-Lolita income. Covers VN material from 1917 to 1990s and some family material pre-1917. The relevant details are in the PDF opened up by this link. (ZK)
Princeton University Library has the volume of Pushkin's poems (see for instance pp. 164-65. 173, 177-78, 182, 186, 189-93, 207-10) and the volume of Tyutchev's poems (see for instance pp. 44-50, 54-59, 62-63, 66-80) that Nabokov used in preparing his translations.
University of Texas, Harry Ransom Humanities Research Center. The inventory this link takes you to is just a foretaste. The Nina W. Matheson Collection actually contains 596 items. Among them are "fourteen rare pre-1940 Russian-language editions, including Stikhi, Nabokov's first surviving book, privately printed in St. Petersburg in 1916, and his Russian translation of Alice in Wonderland, over 200 English-language editions, many in textual or binding variants, and almost all of the rare periodical issues in which Nabokov's Russian-language novels first appeared." (ZK)
Yale University, Beinecke Library. Edmund Wilson papers, including correspondence with VN, and notes on VN.