Responding to a request, here are my main sources for presentation topics. Why the list starts with Gil.
At the start of the Covid pandemic in 2020, Gil Fronsdal recorded an entire introductory course in mindfulness meditation. The link above goes to the first of 9 one hour videos that constitute that course. There is also second related of 8. We can use these several different ways.
Every weekday, IMC has a 7am PDT (10am EDT) a 30 minute Guided Meditation followed by a 10 to 15 minute talk and puts it on YouTube. Each of these videos has a link in its description that will jump to the beginning of the talk. See example above. Most are by Gil but a number of other people do them too. To me, the quality is quite high.
Originally published in 2008, The Issue at Hand by Gil Fronsdal is a book with 32 short chapters that we've used in the past and I'd be happy to use again. The book is online, available as a PDF, Kindle, & paperback. IMC will also send it to you for free if you ask them.
Jack Kornfield is one of Gil's teachers and one of the founders of the Insight Meditation Society on the East Coast and Spirit Rock on the West. Jack has written a lot of books all of which are good sources for presentation topics. He also has a lot of videos on YouTube.
A Path with Heart: Perhaps the most important book yet written on meditation, the process of inner transformation, and the integration of spiritual practice into our American way of life, A Path with Heart brings alive one by one the challenges of spiritual living in the modern world. Written by a teacher, psychologist, and meditation master of international renown, this warm, inspiring, and expert book touches on a wide range of essential issues including many rarely addressed in spiritual books. [from the LA Zen Center website]
In Jack Kornfield's book After the Ecstasy, the Laundry, he writes about the honest development of the wise heart within the cycles of day-to-day life; for instance "amid all the Western masters and teachers I know, some idealistic perfection is not apparent. Times of great wisdom, deep compassion, and a real knowing of freedom alternate with periods of fear, confusion, neurosis, and struggle. Most teachers will readily admit this."
The Wise Heart: A Guide to the Universal Teachings of Buddhist Psychology is yet another good book of his.