Hi nlkaren,
If you'd like to stop receiving mail notifications for junk mail, these steps might help.
We know you mentioned you checked your notifications already, but we're wondering if you checked a specific notification setting.
Change your Mail notifications
1. Go to Settings > Mail > Notifications, then tap Customize Notifications.
2. Tap the email account.
3. Select the setting you want, like Alerts or Badges. When you turn on Alerts, you'll see an option to customize your Sounds by changing the alert tone or ringtone.
The information above is from Customize your Mail notifications on your iPhone, iPad, or iPod touch. We're wondering specifically if you have alerts turned on for either the VIP or Favorite Mailboxes. As you will see from the UI note, that you can get these notifications if you have other Mail notifications turned off, but these custom alerts turned on. You should test by checking each email account and mailbox and make sure that there aren't any alerts that you have set to override the "allow notifications" setting.
If the issue continues, let the community know what you found when you checked each extra setting in Settings > Mail > Notifications > Customize Notifications.
We hope that helps with your question and take care!