80s - hair metal, synthwave/synthpop (think hotline miami, vice city, etc), retro games pre/post crash. all in the 8 bit c64/atari color palette.
90s - grunge and the internet revolution. i think we still need some distance from the 90s to really define the nostalgic points, but a lot of the last few years is undoubtedly swallowed in the new millenia hype.