A table is a data structure that stores IP addresses. It is used to speed up the search and to avoid creating multiple rules.

table <clients> { 192.168.1.0/24, 172.16.0.0/23 }
pass inet proto tcp from <clients> to any

Defining tables in files.

/etc/clientes

192.168.1.0/24
172.16.0.0/23

/etc/pf.conf

table <clients> persist file /etc/clients
pass inet proto tcp from <clients> to any