The Pokemon Indigo League anime (if you can call it an anime. pls don't yell at me). Lisa Frank stuff. N'Sync/Backstreet Boys. Invader Zim. The entire state of Michigan
2013. Mostly because of the hype of all this Animal Crossing: New Leaf hype I had. Plus the games I played and the music I listened to during that time.
And a little bit of 2015. Mostly due to DLC Pack 2 from Mario Kart 8.
The Lengend of Zelda Ocarina of Time title screen. Panfu (This just auto corrected to Panty and I died laughing). Club penguin. Whenever I see one of my original villagers in someone else's town. Petpetpark (I have a vivid memory of playing this when I was waiting at my old dentist for my appointment.)
Playing remakes or remastered versions of games! The last time I felt nostalgic was when I booted up Pokemon Alpha Sapphire for the first time as Emerald was my first Pokemon game. The music and the intro just got to me...