Zach mentions:

Alice A. Bailey / Lucis Trust: https://en.wikipedia.org/wiki/Alice_Bailey
https://www.lucistrust.org/

Sai Baba: https://www.srisathyasai.org/pages/index.html
https://share-international.org/in-depth/maitreya/maitreya-and-other-figures/

Maitreya https://share-international.org/in-depth/maitreya/

Benjamin Creme: https://share-international.org/for-news-media/who-was-benjamin-creme/

the World Teacher: https://share-international.org/for-news-media/who-are-the-masters-of-wisdom/
https://share-international.org/in-depth/masters-of-wisdom/

Masters of Wisdom: https://share-international.org/in-depth/masters-of-wisdom/

Nelson Mandela: https://www.edgemagazine.net/1999/05/benjamin-creme-on-the-emergence-of-the-new-world-teacher/

other Mystic Takeaway podcasts that are mentioned:
https://mystic-takeaway.simplecast.com/episodes/were-always-with-you-an-interview-with-ann-sullivan
https://mystic-takeaway.simplecast.com/episodes/theres-always-help-if-you-ask-for-it-an-interview-with-marijke-op-ten-noort