There appear to be at least three pending cases in the U.S. Supreme Court that were filed by President Trump or his supporters, concerning vote-counting.
Two are from Wisconsin. Trump v Biden, 20-882, was filed December 29 and appeals a decision of the Wisconsin Supreme Court. Trump v Wisconsin Election Commission, 20-883, was filed December 30 and appeals a decision of the Seventh Circuit.
One is from Georgia: Lin Wood v Raffensperger, 20-887, was filed December 30. The plaintiff, attorney Lin Wood, claims standing because Wood is a Georgia voter. It argues that Georgia treated postal voters better than in-person voters.
If anyone knows of other such cases, please comment. So far the U.S. Supreme Court has not acted on any of these three.