I use Spark email client connected to various Gmail accounts for my email and I follow some rules when dealing with email. I heavily use labels for indexing important emails and approach emails in GTD way, actioning on every email and keeping my Inbox as close to 0 as possible.
I subscribe to a few newsletters and unsubscribe from anything that brings no value and only adds noise.
Gmail doesn't have folders. All your messages are saved in All Mail. Everything else (Inbox, Starred, Drafts, user-labels, etc) are just "views" into a subset of the messages in All Mail. And since there's only one copy of any message, if you delete it from any label, you're deleting the only copy, so it's gone from all of them. If you delete a label you remove that "view", but the messages are still in All Mail.
After meetings, its great to send a list of actionable items for all those involved as a summary.
mailyak - Elegant MIME/SMTP email library with support for attachments.
go-imap - IMAP library for clients and servers.
Awesome Emails - Awesome list of resources to build better emails.
gmailfilters - Tool to sync Gmail filters from a config file to your account.
Rspamd - Rapid spam filtering system.
Postmark - Delivers your transactional email to customers on time, every time.
Hakara - Fast, highly extensible, and event driven SMTP server.
BEE Free - Easiest, quickest way to design elegant, mobile responsive emails.
ConvertKit - Email marketing software for creators.
Burner Mail - Hide your personal email address, control who can send you emails, and generate new burners with one click.
heimdall - Self-hosted personal email guardian with one-step deployment.
MailHog - Web and API based SMTP testing.
Mailgun - The all-in-one, intelligent email delivery platform.
Mailgun Logger - Simple admin tool to get Mailgun persistence ad infinititum.
Mailgun with Go - Go library for interacting with the Mailgun API.
Missive - Team inbox and chat tool that empowers teams to truly collaborate around email.
smtp-cli - Command line SMTP client.
Lieer - Fast email-fetching and sending and two-way tag synchronization between notmuch and GMail.
Inbox Zero - How the most productive people manage their inbox.
bulk-mail-cli - Sends automated, dynamic and beautifully designed HTML emails to your mailing list via your terminal.
Accessible Personal Note Email Template - Clean, simple email meant for more personal, 1:1 messages.
reserved-email-addresses-list - List of 1250+ email addresses reserved for security concerns.
Email Mastery - Learn Email Marketing.
SMTP2HTTP (email-to-web) - Tiny software that receive a smtp request (email) and send it to the specified webhook as a http post request.
MailDev - SMTP Server + Web Interface for viewing and testing emails during development.
SparkPost - Predictive email intelligence platform, helping brands predict and optimize email performance.
MailChecker - Cross-language email validation. Backed by a database of over 30 000 throwable email domains.
EmailOctopus - Email marketing for less.
SendGrid - Email Delivery Service.
mime-db - Media Type Database.
Delta Chat - Chat over e-mail.
ImprovMX - Free email forwarding. Email aliases for your domain name.
Really Good Emails - Curated collection of emails.
ETHMail - Email services for Ethereum community.
tmpmail - Temporary email right from your terminal.
Flanker - Python email address and Mime parsing library.
mjml-react - React component library to generate the HTML emails on the fly.
Alter.Email - Transform your HTML emails.
Email Reply Parser - Node library for parsing plain text email content.
Himalaya - Minimalist CLI email client, written in Rust.
MailerSend - Transactional email service that delivers.
Tutanota - Secure email. Free encrypted email.
MailerLite - Create Email Marketing Your Way.
Simplify Gmail - Browser extension that makes Gmail more simple, capable, and respectful.
Hunter - Find email addresses for any website in seconds.
docker-mailserver - Full stack but simple mailserver (smtp, imap, antispam, antivirus, ssl...) using Docker.
go-smtp - ESMTP client and server library written in Go.
Reacher - Open-Source Email Verification API.
check-if-email-exists - Check if an email address exists without sending any email, written in Rust.
Bamboo - Testable, composable, and adapter based Elixir email library for devs that love piping.
smtpd - SMTP server package written in Go, in the style of the built-in HTTP server.
Email Validator - Validates regex, typos, disposable, dns and smtp.
rust-imap - IMAP client library for Rust.
Umbriel - Email marketing platform built with Node.js, TypeScript and DDD concepts.
imap-backup - Backup GMail (or other IMAP) accounts to disk.
Underline - For sending email newsletters, not “campaigns”.
disposable-email-domains - List of disposable email domains.
Email is Good - Site about email productivity.
Gefilte Fish - Automates the creation of GMail filters.
Sieve - Language for filtering e-mail messages.
Leave Me Alone - Easily unsubscribe from unwanted emails.
Revelop - New standard for email.
TXMailer - Transactional Mailer with Liquid and AWS SES.
checkmail - Go package for email validation.
Swoosh - Compose, deliver and test your emails easily in Elixir.
SendGrid Email Blast - CLI tool for sending emails via the SendGrid API.