I

We don’t traditionally think of I as having synonyms, but there are several situations in which it can replace—or be replaced with—another word, phrase, or series of words.

me

Me is sometimes used in place of I in a very informal way, as in Me and Greg are going hiking on Saturday. Such sentences are considered grammatically incorrect, but they’re very common in casual speech.

It’s also commonly used after linking verbs (like is and was) in sentences like It’s me or as an alternative to the awkward-sounding It is I (or This is he or This is she). These kinds of constructions are especially common in situations when identifying yourself at someone’s door or on the phone, or perhaps when pointing yourself out in a photo (Hey, that’s me!). Though considered informal, this use of me is much more widely accepted.

myself

The word myself is sometimes used in place me or I, especially in cases in which there is a compound subject, object, or complement (meaning one that has more than one person or thing), as in John and myself were asked to attend or The event was planned by Kim and myself. 

slang synonyms for I

There are a few creative, informal ways of referring to oneself. One common one is yours truly, which is often used as a way to end a letter before signing your name, but can also be used in place of me, myself, or I in certain cases, as in Guess what? Yours truly is the lucky winner. Other phrases can be used in the same way, such as this guy.