Is that possible to get user's Outlook Assistant field with any standard connectors?
Azure AD don't have "AssistantName" property, Office 365 User don't have also.
Any advice or help will be appreciated!

Is that possible to get user's Outlook Assistant field with any standard connectors?
Azure AD don't have "AssistantName" property, Office 365 User don't have also.
Any advice or help will be appreciated!
It looks like that field is available through the Graph API: https://learn.microsoft.com/en-us/graph/api/resources/contact?view=graph-rest-1.0
Try sending a GET request to this URL: https://graph.microsoft.com/v1.0/me/contacts
using a "Send HTTP Request" under the Office 365 Groups connector in Power Automate. It will return an array of your personal contacts from Outlook and include the assistantName if applicable.
Hope that helps,
Bryan