Searching for "GDZ" (готовые домашние задания / prepared homework answers) for Russian language textbook typically yields results for two main editions widely used in vocational schools (SPO) and senior high school classes:
Meaning of words, synonyms, and idioms.
Deep dives into parts of speech (Nouns, Verbs, Participles, etc.). gdz po russkomu jazyku dudnikov
Various styles of speech (formal, scientific, colloquial). How to Find Specific Solutions etc.). Various styles of speech (formal
You can often find the full textbook (with answer keys in the back for some editions) on Twirpx or similar educational repositories. Standard Content Structure gdz po russkomu jazyku dudnikov