Are Kaladesh cards still Standard legal?
Standard currently consists of the following sets


Kaladesh 
Aether Revolt 
Amonkhet 
Hour of Devastation 
Ixalan 
Rivals of Ixalan


The next rotation will occur when the set after Core 2019 releases. At that time Kaladesh, Aether Revolt, Amonkhet and Hour of Devastation will rotate.