Experimenting with Pypy, I wanted to try Panda3D - while its WHL builds OK,
attempting to install it generates an error about the platform -
$ pip install ./panda3d-1.10.0-cp35-cp35m-linux_x86_64.whl panda3d-1.10.0-cp35-cp35m-linux_x86_64.whl is not a supported wheel on this platform.
Pypys CPython support keeps improving so I wanted to try it anyway - on the Panda3D forum I got a suggestion to try renaming the package.
A post on tensorflow shows how to get pips supported python platforms, here's a snippet to list them:
$ python -c "import pip; print('\n'.join(['-'.join(platform) for platform in pip.pep425tags.get_supported()]))"
Here is some output for pypy3
$ python -c "import pip; print('\n'.join(['-'.join(platform) for platform in pip.pep425tags.get_supported()]))" | sort pp3510-none-any pp3510-none-linux_x86_64 pp3510-none-manylinux1_x86_64 pp3510-pypy3_510-linux_x86_64 pp3510-pypy3_510-manylinux1_x86_64 pp3-none-any py350-none-any py3510-none-any py351-none-any py352-none-any py353-none-any py354-none-any py355-none-any py356-none-any py357-none-any py358-none-any py359-none-any py3-none-any py3-none-linux_x86_64 py3-none-manylinux1_x86_64
Unfortunately, the WHL doesn't work yet, even after renaming:
$ cp panda3d-1.10.0-cp35-cp35m-linux_x86_64.whl panda3d-1.10.0-pp3510-pypy3_510-linux_x86_64.whl $ pip install ./panda3d-1.10.0-pp3510-pypy3_510-linux_x86_64.whl Processing ./panda3d-1.10.0-pp3510-pypy3_510-linux_x86_64.whl Installing collected packages: panda3d Successfully installed panda3d-1.10.0
$ python -c "from panda3d.core import *" Traceback (most recent call last): File "", line 1, in ImportError: /home/stu/.virtualenvs/pypy-nightly-py3.5/site-packages/panda3d/libp3interrogatedb.so.1.10: undefined symbol: PyExc_ImportError
While this doesn't work, it's enough info to report a bug  - if that gets fixed then there are bound to be others, alternately it might just work.