There are 2 repositories under sitecore-forms topic.
The current Sitecore Forms for Sitecore 9 is missing a lot of basic functionality with this extension pack you get extra validation save actions and advanced fields.
Generic Dictionary Facets for Sitecore with Personalization Rules, Sitecore Forms & Experience Profile Support
A connector for sending data from Sitecore Forms to Salesforce Marketing Cloud with an integrated and easy to use UI for the content editor
Module allowing to insert custom javascript to Sitecore Forms submit
Sitecore Forms integration with Sitecore Send (Moosend)
ML face validation for Sitecore Forms
Sitecore Forms DropDown Plus Field - many additional features, settings
Update Contact action for Sitecore 9 Forms