Tolkien’s characters had a rich history. Aragorn could trace his family tree back generations. Meet a dwarf and you would stand a good chance of discovering who is father and grandfather were then and there.
In an incredible project, Swedish engineering student Emil Johansson is attempting to map all these relationships and family connections. The Lord of the Rings Project is a large family tree. You can filter by race. You can see which characters seem to have an inconsistent ancestry, which are non-cannon and which only appear in movies or games.
There are even some brief orcish lines you can follow.