Hi @jster24,
I afraid that there is no way to put Assigned within planner task into the email in Microsoft Flow currently.
If you would like to get the value of Assigned in the planner task within Microsoft flow, you could vote for the similar ideal in the forum below:
https://powerusers.microsoft.com/t5/Flow-Ideas/Planner-Get-more-task-details/idi-p/72538
You could put the Tasks Description into the email by the following workaround:
Make some changes based on the original template. Initialize an array variable to store the information of the Task.
- Use Get Task details action to get the Task description.
2.Use Compose action to store the information needed for each Task. Then append it to the array.
3.Then use the output of the array to create the Html table. Finally, send the table as the body as an email.
4.The configuration of Send email and Filter array actions is the same as the template.



It work, as below:

Take a try.
Best Regards,
Barry