The Tier 1 Innovator visa was launched on 29th March 2019. It has not yet been in operation for a long enough time period for any meaningful data to be collected.
A full list of authorised endorsing bodies is published on gov.uk at the following location:
It is a matter for endorsing bodies to decide if they will only endorse applicants to their own programmes and how to publicise their processes for obtaining Innovator visa endorsement. The Home Office has published guidance for endorsing bodies on how to assess applications at the following link: