Samsung keyboard in a Galaxy tab just got changed to white by Lollipop
I just started using a new keyboard app last week and totally love it. Multiling O Keyboard can be configured any way you like including colors as well as adding and removing keys (like delete). The app can be a bit confusing at first, but if you mess with the settings for a while you'll find it to be great. Plus, it has almost no permissions and takes up hardly any memory.