The Mindfulness Summit:
Learn mindfulness from a range of well-known teachers, including Jon Kabat-Zinn: https://themindfulnesssummit.com/speakers/
The site requires you to register and you can listen to the talks at the time of broadcast and for a short time after, often 24 hours, for free. To listen to talks from other days, including speakers such as Jon Kabat-Zinn, Ruby Wax, Mark Williams and Joseph Goldstein, you have to ‘donate’ $149 (for a life access pass) to a mindfulness charity using a link on the site.
Free Dharma talks that can be listened to online or downloaded: http://dharmaseed.org/
This website provides free access to talks from a great range of speakers. A large number of talks do come from a spiritual background and you will need to make a decision about whether this is something that is appropriate for you . However, if you search for certain speakers and retreats you will find talks specifically offered to teachers of mindfulness based approaches such as MBCT and MBSR. For example, Christina Feldman, John Peacock and Chris Cullen Mindfulness, Insight, Liberation - MBCT/SR Foundations
The new psychology of depression by Mark Williams:
Free podcasts. http://podcasts.ox.ac.uk/series/new-psychology-depression