Finding Raspberry Pi on local network

MAC Address Lookup: MAC addresses of the all devices of Raspberry Pi Foundation start with B8:27:EB:xx:xx:xx or DC:A6:32:xx:xx:xx.

so...

arp -a | grep -i "b8:27:eb\|dc:a6:32"

more

 Other options

nmap -sn 192.168.1.0/24