Though there are many ways in which we can classify the gay but what i suggest herewith is the basic and broad types. It’s my impression that many people believe that there are few types of gay men in this world: those who like to give, and those who like to receive.
the terms top, bottom, and versatile describe roles during sexual intercourse, particularly among gay and bisexual men.
on the basis of preferences and there role top are those who like to penetrate, in other words they would be more interest in the cats which are perform on women in normal sexual intercourse like fucking and so on. these are often called as "active" or "dominate" gay.
Bottom, on the contrary are the person who like to get penetrated. there are those guys who are more interested in which are generally done by females. they prefer to suck, get fuck etc. they are also known as "passive" or "submissive" gay
versatile are good combination of top and bottom characteristic. They would like the reciprocal sex. A good example can be "69"
well.. the other classification can be done on the basis of body hair!!!
There can be two: bear and twink. As name suggest, bear are the one who have hair all over the body and twink is opposite of it with very less or no hair at all.