Hi, I have just released two simple add-ons on Github. Color Picker and Date Range Picker.
If you find any bugs, please let me know.
I have used the template from proof+geist to create. I work it personally so I cannot guarantee there is no bug and it may not apply to all situations.
I have used Google Translate API to translate the add-on, if you found the translation is not valid, please let me know.
It is not for production use. Please use it at your own risk.