While I feel a few of them are pretty obvious, 23-21 will be the most difficult, especially the David Bowie one because as far as I know, only a few EoFFers have heard about that one. I'll give a hint to the GIFs to help you understand my logic.

29. Don't follow the quote, just the idea.
28. The lyrics to the song this GIF is from is the clue. How well do you know your 90s music?
27. Same as 28. How well do you know your 90s anime ending themes?
26. The video game equivalent.
25. Probably should have used the GIF from 29.
24. Kind of obvious... and pretty recent. How well do you know your 70s anime?
23. If you can guess 29, then just focus on the little kid aspect of the video.
22. He's kind of a robot cop I guess.
21. Don't focus on the words, just focus on which persona David Bowie is and think of that theme.
20. I feel this one is obvious. Focus on what San is known as to help.

I'll probably have 29 up later today.