This pranayama has helped me immensely with anxiety. It’s a very simple breath that can reduce anxiety, help improve sleep, manage cravings, and controlling feelings of anger.
You can practice this by sitting upright or laying down while inhaling for 4 seconds, holding the breath 7 seconds, then exhaling for 8 seconds. Keeping the breath ratio is most important, so you can also try starting with inhaling for 2 seconds, holding for 3.5, then exhaling for 4 seconds. There is limited scientific research to support this method, but plenty of anecdotal evidence.
Personally speaking, anytime I’ve felt a surge of anxiety, practicing this breath has been my savior many times! Enjoy!