Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.

scr.im - Don't share your email on public sites.

Drag for Gmail - Transform Gmail into organized To Do lists (like Trello)

Spamty - Spamty is a web service to encrypt an email address and share it on the internet.

KanbanMail - A Kanban board for your emails.

hCaptcha - Do you use a captcha to keep out bots? hCaptcha is a drop-in replacement for reCAPTCHA that earns website owners money and helps companies get their data labeled.