No - unless you’re referring to the ones offered default out of the box. Those are part of “default mappings”. But when you’re making a custom lookup field in Dynamics going from lead to account, supposedly you’d want these to work as actual associations - in HubSpot referring to not the Dynamics account but the corresponding HubSpot account right? In a sync, that’s a complex undertaking, and this is why we are working on rolling out “custom associations” as part of our work on custom object sync.