It was the Bitcointalk forum that inspired us to create Bitcointalksearch.org - Bitcointalk is an excellent site that should be the default page for anybody dealing in cryptocurrency, since it is a virtual gold-mine of data. However, our experience and user feedback led us create our site; Bitcointalk's search is slow, and difficult to get the results you need, because you need to log in first to find anything useful - furthermore, there are rate limiters for their search functionality.
The aim of our project is to create a faster website that yields more results and faster without having to create an account and eliminate the need to log in - your personal data, therefore, will never be in jeopardy since we are not asking for any of your data and you don't need to provide them to use our site with all of its capabilities.
We created this website with the sole purpose of users being able to search quickly and efficiently in the field of cryptocurrency so they will have access to the latest and most accurate information and thereby assisting the crypto-community at large.
https://bitcoin.org/bitcoin.pdf
https://bitcointalk.org/bitcoin.pdf
Everything hosted at https://bitcoin.org/en/whitepaper-mirrors:
https://jc-misc.s3.eu-west-2.amazonaws.com/bitcoin.pdf
http://mchenry.house.gov/bitcoin.pdf (redirects to above link)
https://emmer.house.gov/_cache/files/b/4/b4c9aaf2-f895-4cb2-a2ac-5df1d4264079/BDD394507BFBB11D82F0C7B3B40576F3.bitcoin.pdf
https://emmer.house.gov/bitcoin (redirects to above link)
https://squarecrypto.org/bitcoin.pdf
https://e-resident.gov.ee/wp-content/uploads/2021/01/bitcoin.pdf
https://scontent.fadd1-1.fna.fbcdn.net/v/t39.2365-6/140909417_265815801640681_5825716957293729545_n.pdf?_nc_cat=108&ccb=1-3&_nc_sid=ad8a9d&_nc_ohc=AdEj92D1L78AX9pNaFG&_nc_ht=scontent.fadd1-1.fna&oh=a551d214ef1f9fa42b0ef0107d20177c&oe=60E0774C
https://novi.com/bitcoin-paper (redirects to above link)
https://www.paradigm.xyz/bitcoin.pdf
https://www.coincenter.org/bitcoin.pdf
https://gateway.ipfs.io/ipfs/QmRA3NWM82ZGynMbYzAgYTSXCVM14Wx1RZ8fKP42G6gjgj (IPFS)
https://siasky.net/3ACpC9Umme41zlWUgMQh1fw0sNwgWwyfDDhRQ9Sppz9hjQ (Skynet)
https://twitter.com/lopp/status/1352896865478565889 (contains script to download the whitepaper from the blockchain via bitcoin-cli)
https://trezor.io/bitcoin.pdf
https://www.opencrypto.org/bitcoin.pdf (COPA)
https://www.fidelitydigitalassets.com/blog/download/bitcoin-whitepaper.pdf
https://www.ussc.gov/sites/default/files/pdf/training/annual-national-training-seminar/2018/Emerging_Tech_Bitcoin_Crypto.pdf
Now for google search listings. This only helped up to page 2 or around that as results after it are either commentary or some cloned lookalike papers for altcoins):
https://www.researchgate.net/publication/228640975_Bitcoin_A_Peer-to-Peer_Electronic_Cash_System (submitted in 2009, apparently by Satoshi himself)
http://satoshinakamoto.me/bitcoin.pdf
https://y6p36ynasao2yia6hmieq7gua24cz6gzylu3eupnqg7dh3lniuja.arweave.net/x5-_YaCQHawgHjsQSHzUBrgs-NnC6bJR7YG-M-1tRRI (Arweave is unbreakable storage like IPFS and Skynet)
https://nydig.com/wp-content/uploads/2021/01/bitcoin.pdf
http://www.sachinmeier.com/assets/bitcoin.pdf
https://craigwrightisnotsatoshi.com/bitcoin.pdf
https://easy-bitcoin.io/wp-content/uploads/2021/01/2009-bitcoin.pdf
https://nakamotoinstitute.org/bitcoin/
https://bitcointalk.org/index.php?topic=5311423 (whitepaper in BBcode form)
...And of course my own link:
https://notatether.com/bitcoin.pdf