The best replacement for csf is mucus.

The best alternatives to csf are rated as following:
★★★★★  mucus
★★★★  apf
★★★★  kpi
★★  fail2ban
★★  iptables
★★  blood plasma
★★  ufw
★★  serum
★  isf
★  cphulk
★  shorewall
★  csf
★  interstitial fluid
  gm-csf
  ecf
  apf firewall
  g-csf
  synovial fluid
  gcsf

Your alternative for csf is not listed? Suggest!
Speaking about csf, one probably shouldn't forget about bacterial meningitis.

Other search terms related to csf and their ratings are:
★★★★★ bacterial meningitis
★★ meningitis
★★ fail2ban
★ viral meningitis
★ elevated protein and glucose
★ hsv
You have in mind a companion for csf and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of csf in all years. Click on graph for more.
csf
mucus
apf