Codes ( From newest to oldest )
"exploringbeforetime" - 30 minutes of 2x gold and 2x resources
"1grand" - 1000 gold
"bigexpedition" - 30 minutes of 2x gold and 2x resources
"2k18" - Gives 500 gold
"animaljam" - Gives 1000 gold
"freecode" - Gives 500 gold
"wearegonnaberich" - 1 hour of 2x gold
"release2018" - 500 gold