When adding a button to your email, you can change its hover styling too.

You can learn more about Button design in the linked blog article.

First, add a button, then on the right side of the toolbox, click "hover styling".

Choose the color of your hover style.

Now, when in preview, or send a test email, you can hover over the button and the color will change when hovering on it.

Here is a short video tutorial:

Let us know if you have more questions.