Retrojunk has been near and dear to me for quite some time. You can filter by decade to see just the 90s posts. My personal favorite is their database of commercials. For the 90s kids, you’ll probably remember those more than the shows themselves. They have material I can’t find anywhere else.
The 80sCommercialVault on youtube has unearthed great gems for 90s commercials.
Buzzfeed does it right with their very own Pinterest board of ’90s Nostalgia
My friends radio station! Check it out here. Of course it’s 90s!