Mockupea - Mockupea is an online tool for creating 3d book mockups with a lot of features.
reCAPTCHA - reCAPTCHA is a free security service that protects your websites from spam and abuse.
Stackoverflow '90s - Bring back '90s to Stackoverflow with this extension
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.
Box Shadow Generator - Generating CSS3 multilayer box-shadow has never been easier.
scr.im - Don't share your email on public sites.