There are dozens of collaborative outline creation tools, so I am sharing three different tools that can be used for brainstorming and surveying groups:
Padlet https://padlet.com/ Also a cool curation and content delivery tool. In fact, my daughter’s Spanish teacher used her Padlet as a LMS complete with a moderated Q & A forum.
Dotstorming https://dotstorming.com/ A real-time group brainstorming and decision-making app. Think dot voting gone digital mixed with a Padlet.
Google Forms https://www.google.com/forms/about/ Truly more than a survey tool, you can use Google Forms in conjunction with Sheets to support all sorts of collaboration. For loads of support on using Forms in the classroom, visit the Google for Education Training Center resources on forms.