Night sky with twinkling stars.
Another starry night sky animated background.
As far as animated backgrounds go, this one is more subtle.
Falling snowflakes
Red hearts on a black background with animated sparkles.
Binary 1's and 0's, a bit Matrix like.
A dark background with purple hearts and stars.
Stars on a blue cloth like texture.
Pink hearts
Pink floating hearts on a transparent background, so you can use any background color of your choice!
Multi colored shooting stars, again, this one is also transparent.
Floating bubbles.
Falling pot leaves.
Purple flashing stars.