The best replacement for pem is der.

The best alternatives to pem are rated as following:
★★★★★  der
★★★  crt
★★  pfx
★★  ppk
★  p12
★  x509
★  id_rsa
★  sofc
★  cer
  .crt
  chronic pem
  pgp
  cem
  pkcs12
  ped
  solid oxide

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

Other search terms related to pem and their ratings are:
★★★★★ ssh
keytool
You have in mind a companion for pem and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of pem in all years. Click on graph for more.
pem
der
crt