If you are looking for Android 5.1 or 5.1.1 Lollipop Gapps?
You can use the following Lollipop Gapps for both Android 5.1 or 5.1.1 custom ROMs like CM12.1, LiquidSmooth, Cyanide L, Resurrection Remix, and any AOSP ROM (What is AOSP?).
These Gapps include Play Store and a few Google apps but do not include any bloatware. If you need other Google apps not included in these Lollipop Gapps, please install them using the Play Store after installation of Lollipop Gapps.
Note – These Gapps are NOT COMPATIBLE with newer Android 6.0/6.0.1 Marshmallow or 7.0/7.1/7.1.1 Nougat so please use Nougat Gapps instead.