You can create a formula field with this formula:

LOWER({Your Email Field})

I considered that as a workaround, but I'm trying to avoid including extra language in every automation to point to a calculated field when I just need the email field to have a "formatting" option to convert the existing contents to all lowercase. 

This might be a feature request instead - though it would be nice to have this level of format control over all specialized fields.

You can also create an automation that overwrites the old email address with the results of the formula.

Thanks - I really appreciate the solutions-oriented thinking!

Sadly, I'm trying for a unique identifier as the email address. These are workarounds for the feature I'm really after. I find that I'm having to do a lot of workarounds and use Zapier for automation that should be handled natively in Airtable (hence the suggestion for using scripts).

Fortunately, Aitable has a way of applying amazing new updated features periodically. Fingers crossed this email formatting feature is one of them.

Yes, that would be nice! My former database language, FileMaker, has this feature natively built into the product. 

By the way, I'm not sure how heavily invested you are in Zapier, but since you mentioned Zapier, you might really appreciate taking a look at Make, which is SIGNIFICANTLY cheaper than Zapier yet INFINITELY more powerful & customizable. I wrote an entire post here comparing Make vs. Zapier.

@ScottWorld, you are simply the best!  

You as well! 🙂