Mentor Group Gold
Yes and no.You could Google “corporate service provider”
Results depend on what Google serves you but usually, you'll at most get Vistra and Sovereign on the first page and the others at best start shows up on the second or third page. Scattered in between are regulators, resellers, industry news, and content-filler websites.
The list is a selection of providers I find to be influential, popular, and/or have had good experiences with.
I'm not at all surprised.I have had experience with 5 of the service providers mentioned. It was good with one, neutral with another, and awful with the other 3.