Sortd - Rated the #1 App for Gmail
reCAPTCHA - reCAPTCHA is a free security service that protects your websites from spam and abuse.
KanbanMail - A Kanban board for your emails.
scr.im - Don't share your email on public sites.
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.
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.