what the best approach to do discovery for unknown infra?


I'm new to UD and do like to ask what is the best way to do discovery if the asset in the infra are unknown. I had a list of ip range where I know my device are in there but as the asset is spread out across the ip range, I'm not sure which protocol i should used. what is the best approach I should take to do a basic discovery, like hardware details and ip address.