The best replacement for google keyboard is swiftkey.

The best alternatives to google keyboard are rated as following:
★★★★★  swiftkey
★★★★  swype
★★★★  android keyboard
★★★  samsung keyboard
★★★  aosp
★★★  htc keyboard
★★★  touchpal
★★  lg keyboard
★★  go keyboard
★  kii
  jelly bean keyboard

Your alternative for google keyboard is not listed? Suggest!
Speaking about google keyboard, one probably shouldn't forget about emojis.

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



Google Trends

Scale is based on the average worldwide traffic of google keyboard in all years. Click on graph for more.
google keyboard
swiftkey
swype