How do I get rid of unknown devices on my Google account (2-step verification enabled)?

[anon9014819]

Unknown devices on Google account (2-step verification enabled)

I recently noticed that my Google account has been accessed with devices I don't know anything about (I wasn't able to locate them with Device Manager). Two-step verification has always been enabled.
I own the Windows PC and HTC One but the rest are completely foreign and apparently located in the same country. I've changed my password and removed unfamiliar devices from my account.

Devices & activity: http://i.imgur.com/c9tt2tX.png

EDIT: I've used both BlueStacks and Andy the Android Emulator.

 

[B. Diddy]

Re: Unknown devices on Google account - two-step verification has always been enabled

I wonder if BlueStacks or the Android emulator might access your Google account using some kind of arbitrary proxy, and show up as those random devices.