I just want to say that saying only right-wing groups are promoted by Kremlin is American-centric (understandable since most audience on the Internet are Americans, but this leads to insularity in discussions). The far-left is also funded and promoted by Kremlin, especially in Europe where many far-left parties are Russia-apologists, and either have lukewarm support or blame Ukraine for being invaded. There is little information if the American far-left are co-opted by Kremlin. The leftist group, in the broadest sense of the word, is nonexistent in the US because of decades of fear mongering that made the group too insignificant to gain media attention. But if we count Jill Stein and the Green Party as left, then we can say some sections of the left have been compromised by Kremlin, because Stein had been hesitant to call Putin a dictator in an interview.