Authress

This plugin upgrades the standard WordPress login forms with one powered by <a href="https://authress.io" rel="nofollow ugc">Authress</a> that enables:
<ul>
<li>Universal authentication
<ul>
<li>Over 40 social login providers</li>
<li>Enterprise connections (SAML, Office 365, Google Apps, and more)</li>
<li>Customer configurable SSO connections</li>
</ul>
</li>
<li>Ultra secure
<ul>
<li>User identity</li>
<li>Security access policies</li>
<li>Mitigate brute force attacks</li>
</ul>
</li>
</ul>
Which includes: 
– Azure AD and B2C 
– Office 365 
– WSO2 
– Ping Identity 
– Okta 
– Auth0 
– Keyclock 
– LinkedIn 
– Salesforce 
– Twitter 
– Google Workspace 
– Yahoo 
– Salesforce 
– Hubspot 
– Steam 
– Slack 
– And any custom OAuth2.1, OpenID, or SAML provider
With SSO Login, you can automatically support business and enterprise customers that have important security requirements for their users to use your site and platform.
<h3>Technical Notes</h3>
By using this plugin you are delegating the site authentication and profile handling to Authress. That means that you won’t need to use the WordPress database to authenticate users and the default WordPress login forms will be upgraded to support the new SSO Login flow.
Please see our <a href="https://authress.io/knowledge-base/" rel="nofollow ugc">knowledge base</a> for more information on how Authress authenticates and manages your users.
<h4>Migrating Existing Users</h4>
Authress allows multiple authentication providers. You can have social providers like Facebook, Twitter, Google+, a database of users and passwords (just like WordPress), or you can use an Enterprise directories like, Office365, Google Apps, SAML, OpenID, OAuth2.1. All those authentication providers are supported and more.
<h3>How to customize this plugin</h3>
This plugin provides extension points to make it easier to configure it exactly as you need. Check out the full docs: 
* <a href="https://github.com/Authress/wordpress-sso-login/blob/main/docs/customizations.md" rel="nofollow ugc">SSO Login customizations</a>

SSO Login – Universal (OAuth + SAML)

SSO Login provides user login, business authentication, SSO, Social login, and Single Sign-On for all sites.

onelogin

This SAML plugin eliminates passwords and allows you to authenticate WordPress users (typically editors) against your existing Active Directory or LDAP server as well increase security using YubiKeys or VeriSign VIP Access via OneLogin. OneLogin is pre-integrated with thousands of apps and handles all of your SSO needs in the cloud and behind the firewall.
<ul>
<li>Eliminate passwords in WordPress</li>
<li>Allow users to sign into WordPress with their Active Directory or LDAP credentials</li>
<li>Give users one-click access from your intranet</li>
<li>Increase security using browser PKI certificates or two-factor authentication from Yubico or VeriSign</li>
<li>Easily prevent access from former employees and contractors</li>
</ul>
If you used this plugin before 2.2.0 with just-in-time provision active, Read: https://wpvulndb.com/vulnerabilities/8508 
To mitigate that bug, place the script at the root of wordpress and execute it (later remove it) https://gist.github.com/pitbulk/a8223c90a3534e9a7d5e0a93009a094f

OneLogin SAML SSO

This plugin provides single sign-on via SAML and gives users one-click access to their WordPress accounts from identity providers like OneLogin.

SSO Login – Universal (OAuth + SAML) vs OneLogin SAML SSO