The most common series in Russia. Solutions often cover the textbook parts 1 and 2 as well as the workbook (Arbeitsbuch).
A modern series for schools with an emphasis on the German language. Where to Find Solutions (Reshebniki) skachat reshebnik nemetskogo iazyka 4 klassa
A resource focused on German language learners that often provides links to textbook PDFs and supporting literature. The most common series in Russia