Mentioned in initial comment (probably could have been more clear that those are the certs that require hands on learning):

RHCSA/RHCE/CKA/CCIE are the first ones that come to mind.

Thanks for your response.

Do you believe that those certifications are solid investments for any IT professional (from developer and up) or only for those that are looking to become a SysAdmin/Network Engineer? (forgive me if my terminology isn't spot-on)