A few weeks ago, I asked teams about what tools they would recommend for other teams. Here are the results of the discussion on Facebook Group FLL: Share & Learn .

Engineering Journal/Note taking
Google Science Journal
Google Docs/Drive
Redbooth
OneNote and OneDrive

Sharing Group Files
Google Drive
Dropbox
Google Classroom (very popular, especially among teachers who are also coaches)
Microsoft Teams

Conversations/Chat
Google Hangout
Skype
GroupMe
Facebook Messenger Kids
Google Classroom
Remind.com
Kakao
WhatsApp Groups
Microsoft Teams
Slack

Maintaining Schedules
Google Calendar
Mailing Lists/Team Messaging
Google Group
Fleep
Whatsapp

Team Organization/Project Management
Trello
Slack
Basecamp

Movies/Video Making Tools
iMovie
TouchCast (App)
Animot
Camtasia

iOS and Android Apps for Scoring
Available on FLLTutorials.com and also as iOS and Android Apps

Code Backup Tools
Note: To backup your code, put the date in the file name for version control. Save your code frequently and back it up. You cannot recover code from the EV3 back to a computer. Backup your code on your computer, but keep a copy on a USB stick.
Github
Google Drive
EV3Hub (https://beta.ev3hub.com/)
Dropbox
EV3 Online Tree Visualizer