The recent hubbub about google possibly (or possibly not) deleting old youtube videos from inactive accounts reminded me that I have been holding onto some video's from '04 and '05 which had been remove from youtube over a decade ago. Not even the Internet Archive had a copy of them, until now!
These are four video collecting the opening titles sequences of most Japanese mecha shows from 1960 to 2005, beginning with Tetsujin 28 and concluding with Gundam SEED Destiny. It's a fun look at the stylistic and artistic changes in anime throughout the decades (at least, within the microcosm of robot cartoons).
It was also influential within the early western fandom, being both a nearly complete list of every mecha anime as well as a showcase of what each show looked like and how it presented itself. This was many fans first exposure to most of these shows, and several fansubbers chose their projects from which openings they thought looked particularly cool.
(Or, in the case of 1977's Ginguiser, because it looked egregiously terrible.)
As far as I know, these videos have not been easily accessible for several years now. While there are some youtube playlists that collate openings in the same manner, they have several missing series where copyright holders had videos taken down (and none of them are the original document).