Use these commands to add all RFC1918 networks to a MikroTik RouterOS IP address list:
/ip firewall address-list add address=10.0.0.0/8 list=RFC1918 /ip firewall address-list add address=172.16.0.0/12 list=RFC1918 /ip firewall address-list add address=192.168.0.0/16 list=RFC1918