The following are some of the main providers of identity and access management (IAM) solutions:

1. Microsoft: Microsoft offers Azure Active Directory, a cloud-based IAM solution that provides identity and access management for cloud applications, as well as integrated multi-factor authentication.
2. Okta: Okta is a cloud-based IAM solution that provides single sign-on (SSO), multi-factor authentication, and user management for cloud and on-premises applications.
3. AWS: Amazon Web Services (AWS) provides Amazon Cognito, a cloud-based IAM solution for mobile and web applications that provides user sign-up and sign-in, as well as access control for AWS resources.
4. Google: Google provides Google Workspace (previously G Suite), a cloud-based productivity and collaboration platform that includes IAM features such as single sign-on and user management.
5. Ping Identity: Ping Identity is a cloud-based IAM solution that provides SSO, multi-factor authentication, and user management for cloud and on-premises applications.
6. ForgeRock: ForgeRock is an open-source IAM solution that provides identity and access management for cloud and on-premises applications.

When comparing these solutions, it’s important to consider factors such as the level of integration with existing systems, ease of use, security features, cost, and scalability. You should also evaluate the provider’s reputation and track record, as well as the level of support and documentation provided.

Ultimately, the best IAM solution for your organization will depend on your specific needs and requirements, as well as your budget and resources. It’s recommended to evaluate several solutions and conduct a thorough evaluation before making a decision.