One of my Favorites! Circuit Board LED Christmas Tree!
 
This one is fully assembled and comes with USB cord and wall adapter. Can also be run off 3x AAA batteries (must unplug the cord to run on battery power).
 
If you're interested in a DIY kit, you can find similar ones on Amazon, here's an Amazon Associate link to the one I like https://amzn.to/3Bbcttl