Industry Certification (Linux, Windows, Cisco)

I'm aware that main focus of this community lies on DELL EMC Proven, but for Customer Support Field Technicians and our Field Support there is the advise to gain additional industry certifications on top like Linux, Windows, Network (one of our guys is just looking for Cisco CCNA). Not able to find any track or further information via Education Portal regarding those.

Would you have a recommendation or a person to go?