Hi some known certificate courses are CCNA Cloud (Cisco), CCNP Cloud (Cisco), AWS Certified Solutions Architect, Certificate of Cloud Security Knowledge, Certified System Administrator in Red Hat OpenStack, MCSE: Cloud Platform and Infrastructure (Microsoft). I dont know what certificate will ensure a job in Google or Amazon or Oracle. what I suggest is you check their career pages and see what exactly they are asking. Or you could write to their HR dept asking for information.