Wikipedia

I thought 50501 did it, but it looks like it was a coalition. To the persons who organized this, amazing job and huge kudos to you:

The Hands Off protests were led by a nationwide coalition of organizations, including civil rights organizations, veterans, women's rights groups, labor unions, and LGBTQ+ advocates, for example Indivisible.[3] The protests were in response to what the organisers saw as the administration's overreach on many issues: NATO; schools; libraries; courts; veteran services; fair elections; transgender rights; Social Security; Medicare; Medicaid; the federal workforce; abortion rights; and many others.[4] In a document, organizers said that they had three demands: "an end to the billionaire takeover and rampant corruption of the Trump administration; an end to slashing federal funds for Medicaid, Social Security, and other programs working people rely on; and an end to the attacks on immigrants, trans people, and other communities."[3]

I was there and I hope this momentum continues! Another one in May (not sure the date).