No, there is no limitation. However, the “size” should be as small as possible for easier reading.
Actually there are more and more people who access their email from their smartphones. The use does not want to spend more than 15 seconds waiting to download your email and to read it.
Optimize the size of your marketing emails.
When you send emails you are thinking: videos, images, animations, text… Except that all these have a weight. If bigger your email the more compromised will be the deliverability and your clients will find it difficult to open and read your email.