By left-wing politicians, basically none (while right-wing conspiracy theories are now promoted by tons of right-wing politicians). Among non-politicians: while right-wingers are far more likely to believe in conspiracy theories and the nature of the conspiracy theories they believe are far less tethered to reality on average, conspiracism is still a serious issue on the left.
It's like 50x less of an issue but I deal with so many left-wing conspiracies on a daily basis. I think the right is much worse than the left (on this topic and in general) but quite a lot of the left, or at least the populist left/populist far-left is, to me, its own particular sort of exhaustingly insufferability. I am proudly a left-liberal and not a centrist and never won't be, but I am still at a point where I can no longer tolerate a big sub-faction of the left. (Though I can't tolerate basically any of the right, minus a bit of the anti-Trump center-right.) I am going to lose my mind when I see vast numbers of leftists demand people not vote for the Democratic party presidential candidate in 2028.
It's like 50x less of an issue but I deal with so many left-wing conspiracies on a daily basis. I think the right is much worse than the left (on this topic and in general) but quite a lot of the left, or at least the populist left/populist far-left is, to me, its own particular sort of exhaustingly insufferability. I am proudly a left-liberal and not a centrist and never won't be, but I am still at a point where I can no longer tolerate a big sub-faction of the left. (Though I can't tolerate basically any of the right, minus a bit of the anti-Trump center-right.) I am going to lose my mind when I see vast numbers of leftists demand people not vote for the Democratic party presidential candidate in 2028.