I guess it's really safe cause it's open source, you can make notes on your habits but don't really do that. Its simple. Really fast. Haven't found a way to connect it to notion. In general it's a great app to track you habits. Does its job. Not more, not less.
Habitica - Habitica is a free habit building and productivity application.
fitbit - The Fitbit mobile app is for people who use Fitbit fitness trackers to keep track of their activity goals, food plans, and other fitness related things. Read more about fitbit.
HabitBull - HabitBull
Kinomap - Kinomap app enables you to view videos to get guidelines about how to get into the perfect shape right through their mobile phone.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Strava - The #1 app for runners and cyclists