First Person :
I and WE are the only First Person pronoun. In these two, I is the singular pronoun where as WE is the plural pronoun.
There are other various forms of these two pronouns.
I : My, me, mine
WE : our, ours, us
Second Person :
YOU is the only second person pronoun. YOU is used as both singular and plural.
The other forms of this second person pronoun are :
YOU : your, yours
Third Person :
HE, SHE, IT and THEY are four Third Person pronouns.
HE, SHE and IT are singular pronouns. Whereas, THEY is the only plural third person pronoun.
There are other forms of third person pronouns.
HE : him, his
SHE : her, hers
IT : its
THEY : their, them, theirs