They are all common nouns because they refer to a person that is not the name of a particular person which is a proper noun. [Merriam-Webster](https://www.merriam-webster.com/dictionary/common%20noun) defines a common noun as

 >a word (such as “singer,” “ocean,” or “car”) that refers to a person, place, or thing but that is not the name of a particular person, place, or thing


You could also call them an [agent noun](https://en.wikipedia.org/wiki/Agent_noun): 

>In linguistics, an agent noun (in Latin, nomen agentis) is a word that is derived from another word denoting an action, and that identifies an entity that does that action. For example, "driver" is an agent noun formed from the verb "drive".

[Wikipedia]