Yahoo Mail: Email & Planner

Microsoft Outlook is a full-featured email client with support for multiple services, smart filtering, calendar, and Microsoft 365 integration, but suffers from notification synchronization issues and periodic access failures.

Multifunctional email application with calendar, cloud storage and notes integration, supporting multiple mail accounts with an AI assistant for email summarization.

Samsung Email is a built-in email client for Android supporting POP3, IMAP and Exchange ActiveSync with S/MIME encryption and multi-account management; it operates stably without ads but has compatibility issues on some devices and an outdated interface.

Universal free email client for managing multiple email accounts with push notifications, dark theme, and flexible interface customization. Stable in most cases, but some users experience synchronization, content loading, and performance issues after updates.

K-9 Mail is a free email client with IMAP/SMTP support, OpenPGP encryption, and multiple account management. It operates stably without ads, but has issues with notification synchronization, attachment import, and adding some email providers.

Thunderbird is a free, open-source, privacy-focused email client with IMAP/POP3 support and multiple account management, but has notable issues with notifications, folder synchronization, and compatibility with some providers, particularly Yandex OAuth2.

Email client that consolidates messages from multiple accounts (Gmail, Yandex, Mail.Ru, etc.) into a single interface, but with chronic notification issues and limited service support.

Zoho Mail is a mobile app for managing email, calendar, and contacts with support for multiple accounts, offline mode, and basic data protection (E2E encryption optional). It functions but experiences issues with spam filtering, notifications, and synchronization in some regions.