I'll start.
1: An old Italian veteran of the communist movement
2: Gus Hall
3: William Z. Foster.
4: J.V Stalin.
I've wasted time tracing how many degrees of separation famous people have with Stalin:
Every famous and semi-famous British person is around 4 degrees of separation through Elizabeth II > George Marshall > Stalin since George Marshall attended Elizabeth's coronation. He apparently was seated at a table next to her at some post-coronation dinner, so he's not merely a passive participant.
The entire Cuban Communist Party is like 4 degrees of separation through Fidel/Raul > Brezhnev > Stalin, and most non-gusano Cubans aren't that far away from Stalin either since Raul has been around forever and isn't shy on dealing with average Cubans.
Most of the old-school Cold War ghouls like the Dulles bros and Hoover are Truman > Stalin. Kissinger is Mao > Stalin. Brzezinski is Brezhnev > Stalin. Albright is Brzezinski > Brezhnev > Stalin.
Mao met Stalin at his birthday celebration. Zhou Enlai met Stalin as part of a delegation to request military aid for the Korean War. Chiang Kai-shek is Trotsky(lol) > Stalin, but his son Chiang Ching-kuo actually met Stalin multiple time by virtue of being a de facto hostage, which means modern Taiwanese politicians aren't far removed from Stalin since Chiang Ching-kuo and his successor Lee Teng-hui were in office collectively for 22 years. Deng Xiaoping is Mao > Stalin, but he's also Chiang Ching-kuo > Stalin since they both went to the same school in the Soviet Union. I think none of the newer Chinese leaders beat Elizabeth II > George Marshall > Stalin.
For Black revolutionaries, Nkrumah is Zhou Enlai > Stalin. Sekou Toure is Tito > Stalin since he visited Yugoslavia as part of a delegation as head of state. Lumumba is Nkrumah > Zhou Enlai > Stalin. Huey Newton is Zhou Enlai > Stalin. Kwame Ture is Ho Chi Minh > Stalin surprisingly enough, who he liked to constantly brag about meeting. Malcolm X is Nkrumah > Zhou Enlai > Stalin or Castro > Khrushchev > Stalin. Nasser is Tito > Stalin. Boumediene and Gaddafi are Nasser > Tito > Stalin. MLK is LBJ > Truman > Stalin. Paul Robeson is actually Truman > Stalin where he berated Truman in person for being a racist cracker.
For US presidents, it's:
- FDR: Met Stalin
- Truman: Met Stalin
- Eisenhower: Met Stalin as Supreme Commander
- JFK: Khrushchev > Stalin
- LBJ: Truman visited the White House and gave a speech at Congress while JFK was in office, so I guess it's Truman > Stalin
- Nixon: Eisenhower > Stalin
- Ford: Brezhnev > Stalin
- Carter: Brezhnev > Stalin
- Reagan: Chiang Ching-kuo > Stalin based on this https://taiwantoday.tw/news.php?unit=4&post=4846
- Bush Sr: Eisenhower > Stalin
- Clinton: Elizabeth II > George Marshall > Stalin
- Bush Jr: Elizabeth II > George Marshall > Stalin
- Obama: Elizabeth II > George Marshall > Stalin
- Trump: Elizabeth II > George Marshall > Stalin
- Biden: Elizabeth II > George Marshall > Stalin
For UK PMs, it's:
- Churchill: Met Stalin
- Attlee: Met Stalin
- Eden: Churchill > Stalin
- Macmillan: Churchill > Stalin
- Douglas-Home: Probably Churchill > Stalin or Attlee > Stalin. He attended Elizabeth II's coronation carrying some ceremonial sword, so it's also Marshall > Stalin.
- Wilson: Brezhnev > Stalin
- Heath: This fucker met up with Goring, Goebbels, and Himmler all at once lmao. He was appointed by Churchill as opposition whip, so I guess it's Churchill > Stalin. Otherwise, it's Goring/Goebbels/Himmler > Ribbentrop > Stalin lol
- Callaghan: Brezhnev > Stalin
- Thatcher: I don't think she met Brezhnev, so it's Elizabeth II > George Marshall > Stalin.
- Every PM after Thatcher: Elizabeth II > George Marshall > Stalin
For Catholic popes, it's:
- Pope Pius XII: Churchill > Stalin
- Pope John XXIII: Pope Pius XII > Churchill > Stalin
- Pope Paul VI: Pope Pius XII > Churchill > Stalin
- Pope John Paul I: This is the pope who some people say got whacked by the mob, so he wasn't really able to meet with famous people. I guess, it's Pope Paul VI > Pope Pius XII > Churchill > Stalin
- Pope John Paul II: Elizabeth II > George Marshall > Stalin
- Pope Benedict XVI: Elizabeth II > George Marshall > Stalin
- Pope Francis: Elizabeth II > George Marshall > Stalin
Okay, I've wasted enough time.