Classification of finite groups by Ciro Santilli 34 Updated +Created
As shown in Video "Simple Groups - Abstract Algebra by Socratica (2018)", this can be split up into two steps:This split is sometimes called the "Jordan-Hölder program" in reference to the authors of the jordan-Holder Theorem.
Good lists to start playing with:
It is generally believed that no such classification is possible in general beyond the simple groups.