I finally got around to browsing/searching the Coursera online catalog, and found some online courses that might be of interest to online teachers or prospective teachers . They're free, but if you want the certificate and entry into the employer-searchable database, they're $49 (well worth it, IMO).

Learning to Teach Online (University of New South Wales) - https://www.coursera.org/course/ltto

University Teaching 101 (Johns Hopkins University) - https://www.coursera.org/course/univteaching101

Virtual Teaching Specialization (UCal-Irvine , multi-lesson course) - https://www.coursera.org/specializat...irtual-teacher