Anarchists played a big part in the Russian and Ukrainian revolutions, forming militias, newspapers, and soviets. Free Territory of Ukraine was crushed, some anarchists converted to Bolshevism, anarchists are repressed. Then Stalin appears and dies in the 50s and a gulag rises to revolt and the rebels fly the black banner of the Makhnovists to spite the Soviets.
Then what? What comes next? I found this intriguing Interview with Soviet Syndicalists conducted in 1991 and a little before the fateful collapse of the Soviet Union.
What happened in between? Who were the anarchists in the old Soviet Union, how did they organize, and what did they do? Did they see themselves as the successors of the Makhnovists? Or something else? What did they believe? (Individualism? Anarcho-communism? Platformism?) What did the Soviet authorities think of the anarchists? Do the Soviet archives tell us anything?
In the Tsarist regime in Russia, political opponents were not welcome. This led to exile or exodus of many people, particularly to the USA (where a good amount is known of what happened). Upon arrival to the US, the generally radical eastern Europeans, including Emma Goldman, pretty quickly started to organise. This meant lots of well educated, active and public people in the Anarchist groups and the Industrial Workers of the World. Many of these chose to return to Russia with the revolution.
One such account of the mass return of radicals to Russia, mainly of anarchists/anarchist sympathisers, is given by Ralph Chaplin in Wobbly. According to Chaplin (then editor of Solidarity) most of the Russian unionists (now known as anarcho-syndicalists) in the US chose to leave to fight in the revolution. This was at a time when the true ideology of the rebels was still to be decided, even with Lenin in prominence. As such, the Russians returned to bring the cause of anarcho-syndicalism to the workers revolution. Unfortunately for them, after the revolution was won, the Bolsheviks consolidated their power. The IWW Russians were strongly opposed to Bolshevism and henceforth were part of Stalin's purge.
Another account from Chaplin is of William Haywood, who broke bail to go to Russia and meet Lenin. He was also an anarcho-syndicalist and intent on become a minister for labour/industry and implementing industrial unionism. Haywood was a big name and brought lots of support for the Russians from abroad in publicity and money, so he couldn't be purged like the others as simply. He was quickly back-benched by Lenin as he was also against Bolshevism. He did manage to get Lenin to agree to a settlement in Kuzbass under Haywood's philosophy (https://en.m.wikipedia.org/wiki/Kuzbass_Autonomous_Industrial_Colony), which failed after a few years but had housed Emma Goldman for a while. Haywood, according to Chaplin, became a puppet of the Bolsheviks and subsequently his book that was finished in Russia was disavowed by many of the American anarchists.