I have ASUS Zenfone 5. How could I filter out or identify ARM-native apps on x86 phones in Play Store or in other app market?
The Google Play Store automatically filters your application to devices with compatible CPU architecture. E.g. if you have a library which is only compiled for ARMv5, your app will only show up for devices with ARMv5 and ARMv7 processors. Your device should show you only apps that are compatible to your device.
Short answer: no, you can't filter those apps manually. You may try to uncompress the APK file and check its configuration, but it will be too much complicated work.
If you need a detailed answer, read further. You may not have understood me completely with above answer I gave, let me explain in details:
There are two types of applications based on native library use (native library is compiled with Android NDK)
Apps with Native library (i.e. these apps use native library with CPU specific architecture and these libraries directly execute on CPU instead of using Dalvik VM/ART)
These kinds of apps are filtered in Play Store, because there are multiple version of apps present in the Play Store specific to device (for x86 with x86 compiled library, and for ARM with ARM compiled library. Source - Developer can publish multiple APKs with different configuration)
Apps without Native library (these apps execute on Dalvik VM/ART)
These apps are CPU-architecture-independent, so there is no effect with which device you use these. Also here Dalvik VM will be compiled for your device by device OEM (in your case, ASUS)