https://www.americanbar.org/groups/public_interest/election_... seems to be a big list of the lawsuits, including state courts, but doesn't have links to the filings (argh!).

https://www.brennancenter.org/our-work/court-cases/voting-ri... does have links, but not always to the court filings. (There's a crap-ton of lawsuits in Georgia.)

And then there's https://healthyelections-case-tracker.stanford.edu/cases.