Ivan Vasilievich Changes Profession (Иван Васильевич меняет профессию) is a Soviet comic science fiction film directed by Leonid Gaidai in June 1973. It was one of the most attended films in the Soviet Union in 1973, with more than 60 million tickets sold. The story begins in 1973 Moscow, where engineer Aleksandr "Shurik" Timofeyev (Aleksandr Demyanenko) is working on a time machine in his apartment. By accident, he sends Ivan Vasilievich Bunsha (Yury Yakovlev), superintendent of his apartment building, and George Miloslavsky (Leonid Kuravlyov), a burglar, back into the time of Ivan IV "The Terrible". The pair is forced to disguise themselves, with Bunsha dressing up as Ivan IV (tsar) and Miloslavsky as a knyaz (duke) of the same name. Find it on youtube

The Diamond Arm (Бриллиантовая рука) is a crime comedy film first released in 1969, directed by director Leonid Gaidai and starred several famous Soviet actors, including Yuri Nikulin, Andrei Mironov, Anatoli Papanov, Nonna Mordyukova and Svetlana Svetlichnaya. The Diamond Arm has become a Russian cult film and is considered by many Russian contemporaries to be one of the finest comedies of all time. It was also one of the all-time leaders at the Soviet box office with over 76,700,000 theatre admissions in the Soviet era. The plot of the film was based on a real-life news item about Swiss smugglers who tried to transport jewels in an orthopedic cast. Find it on youtube

The Most Charming and Attractive (Самая обаятельная и привлекательная) is a 1985 romantic comedy. Also on youtube

The Blonde Around the Corner (Блондинка за углом) is a 1984 romantic comedy about an astrophysicist who begins to work at a grocery store where he falls in love with a saleswoman. Various streaming links if you duckduckgo the title

Come and See is a 1985 Soviet anti-war film –https://en.wikipedia.org/wiki/Come_and_See

Aelita Queen of Mars is available free on archive.org

https://en.wikipedia.org/wiki/List_of_highest-grossing_films_in_the_Soviet_Union