Not an anxiety resource per se but I like spiritual teacher Eckhart Tolle's website. It has lots of free stuff, including videos that teach mindfulness and meditation. When I am anxious I am either in the past, experiencing shame, guilt, anger, etc. over something that has already happened, or the future having fear from predicting negative outcomes. Staying in the NOW is the key to my spiritual and emotional health but frequently I need help getting/staying there. The present is Eckhart's main message.