Nostalgic songs tend to be the trend but that is highly subjective. I have found that soundtracks (particularly for orchestral renditions) tend to be great for this. Even if you are not familiar with the source material, it can be an enjoyable experience to hear the whole thing from the beginning to the end (as they are usually prepared for a live audience). The effect is stronger if you are familiar with the source material and I do encourage people to look for series that may have an orchestral rendition.

I included an album that is an example of that.

https://youtube.com/playlist?list=PLMWQMqE7m7Pqt6e7ptBJcvJL-O67ARZi_