The resources are not specific to detransition but cover a range of different issues (anxiety, rumination, shame) that might be relevant for some detransitioned people. 

Resources for coping with trauma responses or acute feelings of anxiety

Mindfulness as a practice for moving away from rumination

Mindfulness is a practice of training attention and can be especially helpful for people who get stuck in rumination. It’s best to start with the three minute exercises and build up from there. It’s also a good idea to try out different audios as there is variation and people tend to have different reactions to different types of mindful practice and different voices etc.

Compassion Focussed Therapy: self compassion as an antidote to shame

Northumbria University/ Northumberland NHS Trust offer a wide range of free, electronic self help resources: http://www.selfhelpguides.ntw.nhs.uk/northumbria/

CCI also has a wide range of free self help materials: https://www.cci.health.wa.gov.au/Resources/Looking-After-Yourself

NHS recommended Mental Health apps: https://www.nhs.uk/apps-library/category/mental-health/