This is the official website of GLTools after Play Store ban.
You can get an APK here.

Update: Due to what happens with Android (scoped storage, exec restrictions and automated bans in Play), I decided to finish my Android journey right here. It was a nice experience, but now it is not.
As Android 10 was not released when GLTools was distributed, I'm not providing any support for it. Furthermore, its security features are incompatible with GLTools-like software.
GLTools was sold to other developers, let's wish them good luck. Under agreement, all premium features of their new GLTools-based software will be provided to the legal users of original GLTools.
This website will redirect you to the page of new GLTools by these developers when/if they release it.