Question: Is there a column type that allows ...

[James_Fussell]

Question: Is there a column type that allows multiple email addresses to be inserted separated by a semi-colon that will work when sending a workflow email to multiple recipients?

[RezaRaoofi]

Have you tried adding more than one recipients email address like picture below? If that does not work in your use case, you should be able to insert comma separated list of email addresses in a text column, and then use a Virtual Column with this formula as recipients: LIST([Email Addresses Text])