I’m a big fan of the Soviet comedy directors Eldar Ryazanov, Leonid Gaidai, and Georgiy Daneliya. Almost anything by them is worth watching, but here are my favorites (filtered for things that have a free YouTube version with good English subtitles, bold are the highest-recommended):
Ryazanov
1966 Beware of the Car (Берегись автомобиля) [YouTube]
Comedy about a benevolent car thief who steals to donate to charity
1975 The Irony of Fate (Ирония судьбы или с легким паром!) [YouTube]
A New Year’s classic premised on the uniformity of Soviet apartment buildings—a guy gets drunk on NYE and ends up in a different city but finds an identical building that his key can access
1977 Office Romance (Служебный роман) [YouTube]
Romantic comedy and satirical portrayal of Soviet office life
1979 The Garage (Гараж) [YouTube]
Comedy set in a single room where people argue about who should lose their garage after the government decides to build a road through the plot they were collectively building garages on
1987 Forgotten Melody for a Flute (Забытая мелодия для флейты) [YouTube]
Satirical romantic comedy about Soviet bureaucracy and its decline in power in the late 80s, great opening song (translate the lyrics)
1991 The Promised Heaven (Небеса обетованные)
Sadly couldn’t find an English-subtitled YT link for this but I like it too much to miss off1
Tragic comedy about the lives of people made recently homeless during the Perestroika period, very sad and of its time
Gaidai
1966 Kidnapping, Caucasian Style (Кавказская пленница, или Новые приключения Шурика) [YouTube]
One of the most famous Soviet comedies—a naive visitor to the Caucasus is convinced to assist in the “bride kidnapping” tradition
1969 The Diamond Arm (Бриллиантовая рука) [YouTube]
Another one of the most famous Soviet comedies—diamonds end up being smuggled in the wrong guy’s cast because he happens to injure himself and say the “codeword” in front of the smugglers’ hideout
1971 The Twelve Chairs (12 стульев) [YouTube]
Film adaptation of the satirical novel by Soviet authors Ilf and Petrov set in post-revolutionary Russia
Daneliya
1977 Mimino (Мимино) [YouTube]
Romantic comedy about a Georgian bush pilot
1986 Kin-dza-dza! (Кин-Дза-Дза!) [YouTube]
Funny low-budget sci-fi
Bonus recommendations
1973 Seventeen Moments of Spring (Семнадцать мгновений весны) [YouTube]
Extremely popular Soviet spy thriller set during WW2
1975 Hedgehog in the Fog (Ёжик в тумане) [YouTube]
Classic short (10mins) animated children’s film, great atmosphere
Maybe I will post a follow-up with my recommended Soviet detective films/series. Edit: this has been posted—link here.

$10 bounty to anyone who finds a link to a free version of this with high-quality English subtitles