The best replacement for iptables is pf.

The best alternatives to iptables are rated as following:
★★★★★  pf
★★★★  ipchains
★★  ufw
★★  netfilter
★★  ipfw
★★  ip6tables
★★  firewalld
★★  nftables
★  shorewall
★  firewall
★  ipfilter
★  iptables
★  route
★  fail2ban
★  ip route
★  tcp wrappers
  hosts.allow
  apf
  hosts deny
  csf
  iproute2
  pix
  hardware firewall
  firestarter
  suse firewall

Your alternative for iptables is not listed? Suggest!
Speaking about iptables, one probably shouldn't forget about nat.

Other search terms related to iptables and their ratings are:
★★★★★ nat
★★ squid proxy
★ ufw
★ dmz
★ transparent proxy
★ connection tracking
You have in mind a companion for iptables and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of iptables in all years. Click on graph for more.
iptables
pf
ipchains