Have you seen that RetroCrush channel too? Its pretty cool and they have their own website dedicated to streaming/releasing retro anime or so too? Like a preservation and re-release type thing I think?
I saw this on their channel by complete chance and was completely obsessed for AGES after that!:
I can definitely relate though, I watch one 90s anime OP or ED and next thing I know, I've spent several hours on a nostalgia trip, a rollercoaster of emotions, a parade of flashbacks and such. As a lot of people say about music especially on Youtube and with Youtube and the Internet itself, it really is like a time machine into the past or a time capsule.