Where those keys were obtained

Centos keys

https://www.centos.org/keys/

Fedora & Epel keys

https://getfedora.org/en/keys/

Mageia

http://mirrors.kernel.org/mageia/distrib/cauldron/x86_64/media/core/release/media_info/pubkey

OpenMandriva

https://raw.githubusercontent.com/OpenMandrivaAssociation/openmandriva-repos/master/RPM-GPG-KEY-OpenMandriva

RosaLinux

https://abf.io/import/rosa-repos/raw/rosa2019.1/RPM-GPG-KEY-ROSA

EuroLinux

https://euro-linux.com/product-signing-keys/

Copr

pushd keys/copr && ../../copr-gpg-download.py --isolate-files && popd

Red Hat

https://access.redhat.com/security/team/key

Navy Linux

https://cdn.navylinux.org/RPM-GPG-KEY-navy-linux-official

openSUSE

https://build.opensuse.org/projects/openSUSE:Factory/public_key

https://build.opensuse.org/projects/openSUSE:Backports/public_key

SUSE

https://www.suse.com/support/security/keys/

Amazon Linux

https://cdn.amazonlinux.com/_assets/11CF1F95C87F5B1A.asc

RpmFusion

http://rpmfusion.org/keys

https://pkgs.rpmfusion.org/cgit/free/rpmfusion-free-release.git/tree/

https://pkgs.rpmfusion.org/cgit/nonfree/rpmfusion-nonfree-release.git/tree/

Adobe

https://get.adobe.com/cz/flashplayer/

Alma Linux

https://repo.almalinux.org/almalinux/RPM-GPG-KEY-AlmaLinux

Brave

https://brave-browser.readthedocs.io/en/latest/installing-brave.html#linux

BlueJeans

https://www.bluejeans.com/downloads

CalcForge

https://www.calcforge.org/RPM-GPG-KEY-calcforge

Datto

https://cpkg.datto.com/DATTO-PKGS-GPG-KEY

https://cpkg.datto.com/DATTO-LEGACYDIST-PKGS-GPG-KEY

Dell

http://linux.dell.com/repo/hardware/dsu/public.key

Dropbox

https://linux.dropbox.com/fedora/rpm-public-key.asc

Google

https://dl-ssl.google.com/linux/linux_signing_key.pub

IUS

https://repo.ius.io/RPM-GPG-KEY-IUS-6

https://repo.ius.io/RPM-GPG-KEY-IUS-7

Intel

https://yum.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS-2019.PUB

https://www.intel.com/content/www/us/en/security-center/pgp-public-key.html

JPackage

http://www.jpackage.org/jpackage.asc

MariaDB

https://mariadb.org/download/

MySQL

https://repo.mysql.com/RPM-GPG-KEY-mysql

Oracle Linux

see bottom of https://yum.oracle.com/faq.html

PostgreSQL RPM Building Project

https://apt.postgresql.org/pub/repos/yum/

Qubes' repositories

https://keys.qubes-os.org/keys/

Remi's repositories

https://git.remirepo.net/cgit/rpms/remi-release.git/plain/RPM-GPG-KEY-remi

https://git.remirepo.net/cgit/rpms/remi-release.git/plain/RPM-GPG-KEY-remi2017

https://git.remirepo.net/cgit/rpms/remi-release.git/plain/RPM-GPG-KEY-remi2018

https://git.remirepo.net/cgit/rpms/remi-release.git/plain/RPM-GPG-KEY-remi2019

https://git.remirepo.net/cgit/rpms/remi-release.git/plain/RPM-GPG-KEY-remi2020

https://git.remirepo.net/cgit/rpms/remi-release.git/plain/RPM-GPG-KEY-remi2021

Rocky Linux

https://dl.rockylinux.org/pub/rocky/8/BaseOS/x86_64/os/RPM-GPG-KEY-rockyofficial

Scientific Linux

http://ftp1.scientificlinux.org/linux/scientific/7x/x86_64/os/RPM-GPG-KEY-sl

http://ftp1.scientificlinux.org/linux/scientific/7x/x86_64/os/RPM-GPG-KEY-sl7

Skype

https://repo.skype.com/data/SKYPE-GPG-KEY

UnitedRPMs

https://github.com/UnitedRPMs/unitedrpms/blob/master/URPMS-GPG-PUBLICKEY-Fedora-24

VirtualBox

https://www.virtualbox.org/download/oracle_vbox.asc

Microsoft

https://packages.microsoft.com/keys/microsoft.asc

Zimbra

https://files.zimbra.com/downloads/security/public.key

Zoom

https://zoom.us/linux/download/pubkey

How to verify the GPG key

Run gpg2 key_file and compare the output with fingerprints on pages above.

TODO

Add more gpg keys from this list https://rpmfusion.org/FedoraThirdPartyRepos