I've reviewing a lot of Shopify stores over the past few years and I've started to notice patterns with how they handle email marketing.
Stores that are very aggressive with their list opt-ins.
Stores that hide their email list.
Stores that send a lot of emails.
Stores that rarely send any emails.
From what I've seen the aggressive stores tend to be equally aggressive with both opting in subscribers and sending emails. Some cross the line into over-aggressive but those are the minority (though they are a very visible minority).
The more common type is that a store that doesn't promote their email list at all and then they rarely email. They end up getting so few subscribers over time who never buy anything, so they don't invest any more time into email.
Or a store promotes signing up for their list like crazy with multiple pop-ups, a spinner wheel, and exit intent popup...
but then never email or only email once in a blue moon.
If either of those describes you, I'm giving you my permission to promote your email list more and send more emails.
You never needed my permission of course, but since you now have it you can use it.
Email is one of the most powerful ways to attract and keep customers. Every marketing channel is judged against email. Ads. Social media. SEO. Interestingly, every channel also boosts email making it better.
It's time for you to make use of it.
P.S. I don't have any Shopify apps that help with email marketing in general, but if your store has a moderate level of customers then Repeat Customer Insights might help you spot some segments you can target with specific email content.