
Top licenses used in python:
https://snyk.io/blog/over-10-of-python-packages-on-pypi-are-distributed-without-any-license/

Method
From the author: "First, I collected the metadata of all packages and all of their released
versions on PyPI. This was done over several days in early August 2018. At the
time there were nearly 150,000 packages on PyPI."

mit ✅
bsd2 ✅
gpl3 ✅
apache2 ✅
agpl3 ✅
lgpl3 ✅
gpl2 ✅
bsd3 ✅
zpl ✅
isc ✅
mpl2 ✅
gpl3+
psf ✅
public_domain
wtfpl ✅
unlicense ✅
lgpl2.1 ✅
lgpl2 ✅
agpl3+
cc0_1 ✅
lgpl3+
gpl2+


List from pypi.org (82) https://pypi.org/classifiers/

License :: Aladdin Free Public License (AFPL) ✅
License :: CC0 1.0 Universal (CC0 1.0) Public Domain Dedication ✅
License :: CeCILL-B Free Software License Agreement (CECILL-B) ✅
License :: CeCILL-C Free Software License Agreement (CECILL-C)
License :: DFSG approved
License :: Eiffel Forum License (EFL) ✅
License :: Free For Educational Use
License :: Free For Home Use
License :: Free To Use But Restricted
License :: Free for non-commercial use
License :: Freely Distributable
License :: Freeware
License :: GUST Font License 1.0
License :: GUST Font License 2006-09-30
License :: Netscape Public License (NPL) ✅
License :: Nokia Open Source License (NOKOS) ✅
License :: OSI Approved :: Academic Free License (AFL) ✅
License :: OSI Approved :: Apache Software License ✅
License :: OSI Approved :: Apple Public Source License ✅
License :: OSI Approved :: Artistic License ✅
License :: OSI Approved :: Attribution Assurance License ✅
License :: OSI Approved :: BSD License ✅
License :: OSI Approved :: Boost Software License 1.0 (BSL-1.0) ✅
License :: OSI Approved :: CEA CNRS Inria Logiciel Libre License, version 2.1 (CeCILL-2.1)
License :: OSI Approved :: Common Development and Distribution License 1.0 (CDDL-1.0) ✅
License :: OSI Approved :: Common Public License ✅
License :: OSI Approved :: Eclipse Public License 1.0 (EPL-1.0)
License :: OSI Approved :: Eclipse Public License 2.0 (EPL-2.0) ✅
License :: OSI Approved :: Eiffel Forum License ✅
License :: OSI Approved :: European Union Public Licence 1.0 (EUPL 1.0)
License :: OSI Approved :: European Union Public Licence 1.1 (EUPL 1.1) ✅
License :: OSI Approved :: European Union Public Licence 1.2 (EUPL 1.2)
License :: OSI Approved :: GNU Affero General Public License v3 ✅
License :: OSI Approved :: GNU Affero General Public License v3 or later (AGPLv3+)
License :: OSI Approved :: GNU Free Documentation License (FDL)
License :: OSI Approved :: GNU General Public License (GPL)
License :: OSI Approved :: GNU General Public License v2 (GPLv2) ✅
License :: OSI Approved :: GNU General Public License v2 or later (GPLv2+)
License :: OSI Approved :: GNU General Public License v3 (GPLv3) ✅
License :: OSI Approved :: GNU General Public License v3 or later (GPLv3+)
License :: OSI Approved :: GNU Lesser General Public License v2 (LGPLv2) ✅
License :: OSI Approved :: GNU Lesser General Public License v2 or later (LGPLv2+)
License :: OSI Approved :: GNU Lesser General Public License v3 (LGPLv3) ✅
License :: OSI Approved :: GNU Lesser General Public License v3 or later (LGPLv3+)
License :: OSI Approved :: GNU Library or Lesser General Public License (LGPL)
License :: OSI Approved :: Historical Permission Notice and Disclaimer (HPND) ✅
License :: OSI Approved :: IBM Public License ✅
License :: OSI Approved :: ISC License (ISCL) ✅
License :: OSI Approved :: Intel Open Source License ✅
License :: OSI Approved :: Jabber Open Source License
License :: OSI Approved :: MIT License ✅
License :: OSI Approved :: MITRE Collaborative Virtual Workspace License (CVW)
License :: OSI Approved :: MirOS License (MirOS) ✅
License :: OSI Approved :: Motosoto License
License :: OSI Approved :: Mozilla Public License 1.0 (MPL)
License :: OSI Approved :: Mozilla Public License 1.1 (MPL 1.1)
License :: OSI Approved :: Mozilla Public License 2.0 (MPL 2.0) ✅
License :: OSI Approved :: Nethack General Public License
License :: OSI Approved :: Nokia Open Source License ✅
License :: OSI Approved :: Open Group Test Suite License ✅
License :: OSI Approved :: Open Software License 3.0 (OSL-3.0) ✅
License :: OSI Approved :: PostgreSQL License ✅
License :: OSI Approved :: Python License (CNRI Python License)
License :: OSI Approved :: Python Software Foundation License ✅
License :: OSI Approved :: Qt Public License (QPL) ✅
License :: OSI Approved :: Ricoh Source Code Public License ✅
License :: OSI Approved :: SIL Open Font License 1.1 (OFL-1.1)  ✅
License :: OSI Approved :: Sleepycat License ✅
License :: OSI Approved :: Sun Industry Standards Source License (SISSL) ✅
License :: OSI Approved :: Sun Public License ✅
License :: OSI Approved :: The Unlicense (Unlicense) ✅
License :: OSI Approved :: Universal Permissive License (UPL) ✅
License :: OSI Approved :: University of Illinois/NCSA Open Source License ✅
License :: OSI Approved :: Vovida Software License 1.0 ✅
License :: OSI Approved :: W3C License ✅
License :: OSI Approved :: X.Net License ✅
License :: OSI Approved :: Zope Public License ✅
License :: OSI Approved :: zlib/libpng License ✅
License :: Other/Proprietary License
License :: Public Domain
License :: Repoze Public License


Existing

# Public domain
PUBLIC = 0
UNLICENSE = 1 ✅
# Permissive GPL compatible
MIT = 10 ✅
BOOST = 11 ✅
BSD = 12 ✅
ISC = 13 ✅
NCSA = 14 ✅
PSFL = 15 ✅
# Other permissive
APACHE = 20 ✅
ECLIPSE = 21 ✅
ACEDEMIC_FREE = 22 ✅
# LGPL
LGPL_X = 30
LGPL_2 = 31 ✅
LGPL_3 = 32 ✅
LGPL_2_PLUS = 33
LGPL_3_PLUS = 34
# GPL
GPL_X = 40
GPL_2 = 41 ✅
GPL_3 = 42 ✅
GPL_2_PLUS = 43
GPL_3_PLUS = 44
# AGPL
AGPL_3_PLUS = 50 ✅
# Other copyleft
MPL = 60 ✅
EU = 61 ✅

# No License
NO_LICENSE = 200

>400 licenses 100 of which are marked copyleft
Someone else has done something pretty similar here by the looks of things
https://github.com/EmbarkStudios/spdx/blob/d38660119f5abb37dd13a5bfc86966ba68440b59/src/identifiers.rs

OpenSUSE have a long list of identifiers
https://github.com/rpm-software-management/rpmlint/blob/4a5b078a7be613a7c5d3e4e45f084a4a74970533/configs/openSUSE/licenses.toml

Here's a list of 31 licenses
https://github.com/ufal/public-license-selector/blob/97a7af0a7af00829bf43958669c79334cf77015c/src/definitions.coffee

SPDX license data from
https://github.com/spdx/license-list-data/blob/master/json/licenses.json
