Cool tool! I had to double check because I thought Vim was much older. Indeed, Vim goes back to 1991 (https://en.wikipedia.org/wiki/Vim_(text_editor)). This is a great view of the last 20 years of Vim.
nvi and vile were two names that spring to mind, but I know there were others.
Looks like vile itself started in 1992:
> This chart shows the last 20 years of development as seen in the Vim git repository.