I've collected various original Bitcoin sources here: https://github.com/benjyz/bitcoinArchive

It would be a good addition to add newer Crytpocurrencies (their sources and whitepapers). If you want some added please make a pull-request

Original Eth wp:
http://web.archive.org/web/20140111180823/http://ethereum.org/ethereum.html

Original Nxt code:
https://gist.github.com/benjyz/b9cfa877710ff6c42877

Dash:
https://www.dash.org/wp-content/uploads/2015/04/Dash-WhitepaperV1.pdf

Peercoin:
https://peercoin.net/assets/paper/peercoin-paper.pdf