nma[p can be used to scan your local network for valid IP address – IE to find other RPi or laptops on your local network.
install:
sudo apt install nmap
scan your local network if on 192.168.0.0
sudo nmap -sn 192.168.0.0/24
source page:
https://howchoo.com/g/mjk3m2e2njy/find-your-raspberry-pis-ip-address