* [Mailspring 1.19.0](https://github.com/Foundry376/Mailspring) – Beautiful, fast mail client for managing emails across multiple platforms.

* [Premailer v1.29.0](https://github.com/premailer/premailer) – Converts CSS into inline styles, fixes relative paths, checks CSS for email-client compatibility, and generates plain-text output.

* [Mailtrap Node.js client v4.5.0](https://github.com/mailtrap/mailtrap-nodejs) – Node.js client for sending transactional and bulk emails with sandbox mode, attachments, and API token-based authentication.

* [go-premailer v1.32.0](https://github.com/vanng822/go-premailer) – Inlines CSS into HTML email for Go.

* [Send mail GitHub Action v16](https://github.com/dawidd6/action-send-mail) – GitHub Action that sends emails to multiple recipients with plain/HTML/multipart bodies, attachments, Markdown-to-HTML conversion, and SMTP configuration.