Breathe2Relax - Breathing exercises to practice diaphragmatic breathing.
Othership - Othership offers 500+ music-driven guided breathwork classes to lift you up and ground you down: kickstart your day, cultivate focus, fight fatigue, sleep deeper, regulate your emotions, and learn the science-backed how + why of breathing mechanics.
Lungy - Next-gen breathing exercises that respond to every breath
QuietKit - Guided meditation for beginners (for free)
Breathe - Relax from anxiety with reminders to breathe deeply.
MindfulDevMag - Mindfulness for Developers Magazine