Read (it) (by) yourself !

What is a correct : “Read it yourself,” “Read yourself,” or “Read by yourself” ?

Read it yourself - correct - a command or instruction that someone should read a particular piece rather than having it read to them.
Read yourself - can be correct. The usual context would be a command and it is likely that the speaker is somewhat annoyed/frustrated that the person was expecting to be read to.
Read by yourself - correct - a command or instruction that someone should read independently.