There are multiple options for how to translate John 8:58, but a typical one is
"before Abraham was born, I am!" (Berean Study Bible)
Although 'ego eimi' used in this sort of grammatical way is often translated as "I am he" or "I am the one", and indeed is commonly translated throughout John in that way, including 3 instances right around 8:58 (8:24, 8:28, and 9:9 - also see John 4:26 where it is explicitly tied to being the Messiah), at John 8:58 it is usually translated as simply "I am", seemingly due to the unusual structure of the sentence.
Some go further, such as the NKJV, and translate it as "I AM", similar to how LORD is translated in place of Yahweh in the Old Testament. It seems a common argument for translating the phrase at 8:58 as "I AM" is that there must be a claim of pre-existence involved, and there's only one option in claiming pre-existence, namely that Jesus = Yahweh = God (see multiple answers to the question How do Trinitarians who argue the 'ego eimi' at John 8:58 ought to be translated 'I AM' explain the lack of reactions to the same phrase?). Therefore, the 'ego eimi' must be a claim to be Yahweh.
Yet, it seems there are multiple options in Christianity. I am familiar with a few.
Jesus pre-existed Abraham as Yahweh = God. (Common Trinitarian interpretation.)
Jesus pre-existed Abraham as the Logos, which is subsidiary to Yahweh. (Common early church Logos theorist view.)
Jesus pre-existed Abraham notionally as the Messiah. (Biblical Unitarian interpretation, typically translated instead as "I am the one" such as with the REV, i.e., I am the one whose day Abraham saw at 8:56.)
Jesus pre-existed as an angel. (Jehovah's Witness interpretation.)
Jesus pre-existed as a soul in communion with God. (Christian Science interpretation.)
Are there other options in the Christian literature for pre-existence (real or notional) of Jesus that extends from before Abraham to when Jesus is speaking?