Thanks for reaching out. Welcome to the community!
First up, I'd recommend having a quick scan of the email accounts you own (including any spam or junk folders) for emails from Spotify. If you have any, it's likely there's an account associated with that email address. Alternatively, you can enter any email addresses you use into Spotify's password reset form. If there's an account associated with it, Spotify will let you know.
If you happen to know your account's username, you could also log into your account using your username and password.
Finally, I'd recommend taking a look at the "Finding accounts" support article for some more steps to find the email/username associated with your account.
Let me know how it goes — I'll be here in case you need any further help 🙂
Help others find this answer and click "Accept as Solution".
If you appreciate my answer, maybe give me a Like.
Note: I'm not a Spotify employee.