The SlavoLingo project includes 17 complete A1 courses for LibreLingo of the following languages: Interslavic, Belarusian, Church Slavonic, Czech, Kashubian, Old Church Slavonic, Lower Sorbian, Croatian, Upper Sorbian, Polish, Rusyn, Russian, Slovak, Slovenian, Serbian, Silesian, and Ukrainian.
You can find the source code for all the courses with the script to compile them all here.