The best replacement for sha256 is md5.

The best alternatives to sha256 are rated as following:
★★★★★  md5
★★★★  sha1
★★★★  sha512
★★★  scrypt
★★★  bcrypt
★★  scrypt mining
★★  md5 speed
★★  sha 2
★★  hmac sha256
★★  pbkdf2
★  sha256managed
  sha1 performance
  md5 sha1
  md5 hash

Your alternative for sha256 is not listed? Suggest!
Speaking about sha256, one probably shouldn't forget about rsa.

Other search terms related to sha256 and their ratings are:
★★★★★ rsa
★★★★ ecdsa
You have in mind a companion for sha256 and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of sha256 in all years. Click on graph for more.
sha256
md5
sha1