Here are some softwares created by Guokai(Jackie) Han

Advanced Form Notifications
Advanced Form Notifications

Advanced Form Notifications is a Google form add-on, it can help you send email notifications to users and you, and can check new responses or close the form.

Outdated Doc Detector
Outdated Doc Detector

Outdated Doc Detector is a Chrome extension. It can check whether the translation page is behind the corresponding English version.

Re-newtab
Re-newtab

A redesigned, productive and pragmatic newtab alternative.

Gmail Add-on for YouTube
Gmail Add-on for YouTube

GMAYT is a Gmail add-on for YouTube. When you open an YouTube email notification you subscribed, it can show you more information about the video.

Contact Manager for Gmail
Contact Manager for Gmail

Contact Manager is a Gmail add-on that integrate Google Contacts with Gmail. It can list, edit contacts in the email or create new contacts.

Gmail Debugger
Gmail Debugger

Gmail Debugger is a Gmail add-on. It can show gmail's raw and meta data. This add-on is mainly for developers.