B747 Captain reported a number of unrelated EICAS messages appearing during climb in VMC conditions. The Captain returned to the departure airport and landed safely.

Narrative

Just after takeoff; we began receiving EICAS messages for multiple failures. Pack 2; (Electronic Engine Control) EEC; TAT Probe; Auto Throttle; etc. LNAV & VNAV were armed but would not capture. Auto throttle would not engage. EEC's would not all go into alternate. We completed all QRH non-normal checklists and decided to return to ZZZ airport. We flew manually; without automation or navigation guidance; and made a safe landing at the departure airport. Identification- just after takeoff; during climb; EICAS message began appearing. There were NO EICAS messages during taxi or take-off roll. Cause -the maintenance department pulled an entire row of circuit breakers during routine service. They did not tag the open circuit breakers. They did not record the pulled circuit breakers in the aircraft maintenance log. They did not push the circuit breakers back in after completing their service. They returned the aircraft back into service without pushing the CB's back in. Response - performed all non-normal QRH checklists. Turned aircraft around and returned to ZZZ for a safe landing. Suggestions - this is a question for the maintenance department. Following procedures and guidelines. Tagging open CB's. Logbook entries. Returning all switches; handles; levers; and CB's to their proper positions before returning an aircraft back into service.