Are there any single sign on systems that can work with both suite crm and wordpress so when you login to one it logs into the other and can pass data between the two?
This is not just a question of single sign-on, it’s a matter of defining what-who-does-where in the two systems.
So you have a bunch of Wordpress Portals in the SuiteCRM Store, these are designed to have an area in your web site where external users can do some work in some SuiteCRM modules. This is not the same thing as making (one SuiteCRM User = one Worpdress user).
You can also have just one login, and then access SuiteCRM via the REST API.
There are many ways to architect the solution, but I don’t know enough about your requirements to advise.
Any way, for all your “is there a plugin” questions, simply search the SuiteCRM Store, they’re all there.
Try this plugin WordPress SuiteCRM User Bridge
Try WordPress plugin WPSuiteCRM U-Bridge that synchronizes user accounts and associated attributes between WordPress and SuiteCRM or