France aided the UK and was the UK's best ally during the campaign. They declared an arms embargo against Argentina, they allowed use of french controlled ports in West Africa, they provided lots of information about Exocet missiles and they aided British intelligence in preventing Argentina obtaining more of them.
Our biggest "frenemies" during the Falklands were the USA and Israel. Israel were selling them arms (or attempting to) throughout the war and the USA was neutral (with lots of Argentinian sympathy) until their hand was forced.
> USA was neutral (with lots of Argentinian sympathy) until their hand was forced.
Ronald Reagan and Margaret Thatcher: A Political Marriage would disagree with you. Reagan wanted to keep the USSR out of Argentina so the public line was neutrality even with Thatcher pushing him to do otherwise. Behind the scenes the US provided intelligence to Britain.
The USA was, at least at first, divided on the issue and didn't exactly come swingeing down on the British side - many members of the Reagan administration thought that aiding the UK would hamper their anti-communist efforts in South America generally and I guess as hegemon they just wanted the whole inconvenient problem between two US allies to go away.
Later when it became clear that the UK was going to war, that was that. They did support the British position but didn't get entangled publicly for their own reasons, not least there's no point getting involved if your ally can take care of it anyway.
Our biggest "frenemies" during the Falklands were the USA and Israel. Israel were selling them arms (or attempting to) throughout the war and the USA was neutral (with lots of Argentinian sympathy) until their hand was forced.