In retirement, I still remain active in California's community college system, serving as a course reviewer in its C-ID Program. An active effort for faculty involves the creation and utilization of "free textbooks" in what is called the OER program. Two potential resources out there that relate to CompTIA certifications are available for consideration. There may be more, and if you locate them, I'd appreciate it if you'd provide the link.
Network+
Security+
Steve Linthicum, JD, CISSP
Professor Emeritus
Network+
Security+
Steve Linthicum, JD, CISSP
Professor Emeritus