What traces of the former community of Indo-Europeans do you know?

First of all, this is linguistic affinity, traces of the ancient proto-language, preserved to this day in all languages ​​of the Indo-European group, from Russian to Sanskrit. It was the linguistic relationship that became the basis for the theory of the common origin of the Indo-European peoples – all other traces, including archaeological finds, are secondary. Moreover, it is the study of Indo-European languages ​​and the isolation of their most ancient component that makes it possible to get an idea of ​​the way of life of the first Indo-Europeans. Also, the peoples of the Indo-European group are united by the kinship of religious beliefs (a similar idea of ​​the supreme gods, the names of deities), the similarity of traditional methods of management, the similarity of archaeological finds (ceramics, ceramics, weapons, jewelry), family and household customs, which are recorded by historians, foreign travelers and ethnographers … Finally, even in the most ancient songs, legends and chronicles telling about legendary times, you can find a real historical basis.