3rd party Fitbit Charge 4 bands reviews (in the comments) : r/fitbit
Fitbit tips and tricks
LEAKED PHOTOS: Fitbit's new headphones and troubled smartwatch
Are Fitbit Versa bands compatible with Versa Lite? | iMore
Amazon.com: 6 Pack Sport Bands Compatible with Fitbit Versa 2 / Fitbit Versa/Versa Lite/Versa SE, Classic Soft Silicone Replacement Wristbands for Fitbit Versa Smart Watch Women Men (6 Pack A, Small) : Electronics
GEAK 15 Pack Bands Compatible with Fitbit Versa 3/Fitbit Sense Bands, Soft Replacement Wristband for Fitbit Sense/Versa 3 Bands Women, Flexible Waterproof Sport Watch Strap for Women Men Small 15 Pack : Electronics
Fitbit Charge 4 adds GPS but doesn't work with third-party apps - CNET
Fitbit smartwatches, trackers are burn hazards, claims a lawsuit
Fitbit OS 3.0 Brings New Third-party Apps, Improved Dashboard - Thurrott.com
The Fitbit Versa Lite Hands-On: Everything you ever wanted to know | DC Rainmaker
Solved: "Layers" watch face (default clockface) - Fitbit Community
Fitbit Charge 4 adds GPS but doesn't work with third-party apps - CNET
Fitbit OS 3.0 brings more third-party app support, including Couch to 5K - The Verge
8 Ways to Connect Your Fitbit to Third Parties - dummies
Fitbit SDK
Fitbit Ionic and Versa smartwatches get support for more third-party apps