Repeating the main theme but with some variety in the theme - perhaps with addition/subtraction of instruments, increased/decrease in volume, or slightly different notes being played or sung. The variations can be subtle.

I love the slow build up in the intro of Station To Station where riffs from different instruments were slowly added and you have a gradual build up of repeating riffs.

However my general principles is
that all music no matter how free or pirated it is cost at the minimum your time. Don't waste it

Repeating something without changes in the arrangement whatsoever seems an ultimate waste of my time.