QQmail

Amazon WorkMail is a secure, managed business email and calendar service with support for existing desktop and mobile email client applications. Amazon WorkMail gives users the ability to seamlessly access their email, contacts, and calendars using the client application of their choice, including Microsoft Outlook, native iOS and Android email applications, any client application supporting the IMAP protocol, or directly through a web browser. You can integrate Amazon WorkMail with your existing corporate directory, use email journaling to meet compliance requirements, and control both the keys that encrypt your data and the location in which your data is stored. You can also set up interoperability with Microsoft Exchange Server, and programmatically manage users, groups, and resources using the Amazon WorkMail SDK. Amazon WorkMail features simple, low, monthly per-user pricing and costs $4 per user per month which includes 50GB of storage per user.

Protects against spam and fraud. Log into the app with your PIN and fingerprint. Put messages on a timer so you can write them in advance and send them when it's time. Yandex Mail can look like your standard email client, or any other way you want. Join multiple Yandex inboxes under one Yandex Mail account. Incoming mail is checked for viruses, and suspicious messages are sorted into the Spam folder. Add your mobile phone number and never worry about getting locked out. If you prefer to go through your mail in the evening, turn on the dark theme. It lowers screen contrast and is more comfortable on the eyes. You can also change sounds in the settings. Choose the one you like. Finally, you can swipe the screen to delete or archive your email. Customize it to your liking. If a sender attaches a picture, you see its thumbnail next to the subject of the message in the Inbox.