Baracuda - http://www.barracudacentral.org/report/website-category/www.example.org

Bluecoat - https://sitereview.bluecoat.com/sitereview.jsp

Bright Cloud - https://www.brightcloud.com/tools/url-ip-lookup.php

CheckPoint- https://www.checkpoint.com/urlcat/

Cisco - Scansafe -  https://securityhub.cisco.com/web/submited_urls

Cisco - WSA - https://www.cisco.com/c/en/us/support/docs/security/web-security-appliance/117930-technote-csc.html

Cisco Umbrella (aka opendns) - dig example.com.cat.opendns.com TXT @208.67.222.222 (https://support.umbrella.com/hc/en-us/articles/360000085403-How-to-find-the-Content-Category-Classification-for-a-Domain-)

Forcepoint - (used by virustotal) https://csi.forcepoint.com/

Fortinet - http://url.fortinet.net/

Ironport -  https://www.talosintelligence.com/reputation_center/lookup?search=xyz.com

Juniper - http://mtas.surfcontrol.com/mtas/JuniperTest-a-Site.php

McaFee - https://www.trustedsource.org/?p=mcafee

PaloAlto - https://urlfiltering.paloaltonetworks.com/

SonicWall - http://cfssupport.sonicwall.com/Support/web/eng/newui/viewRating.jsp

TitanHQ -  https://tools.zvelo.com/

TrendMicro - https://global.sitesafety.trendmicro.com/

WatchGuard -  http://mtas.surfcontrol.com/mtas/WatchGuardTest-a-Site.php

WatchGuard  - https://www.watchguard.com/securityportal/UrlCategorization.aspx