Whom (object pronoun for people, especially in non-defining relative clauses (in defining relative clauses we colloquially prefer who)
Which
Whose
subject or object pronoun which refers to time
Subject or object pronoun for people, animals and things in defining relative clauses (who or which are also possible)
Who
subject or object pronoun for people
possession for people animals and things
When
subject or object pronoun for animals and things
That