Hi @fverdu,
Do you want to send out a reminder email before the expiration date? Do you have a Date (date only) column in the SharePoint list?
Say you want to send a reminder email 3 days before the expiration date, you could use Filter query to filter the items. The code in the Filter query is:
Date eq formatDateTime(addDays(utcnow(),3),'yyyy-MM-dd')
Note: Date is of type date and time and is Date only formatted in the list, the function formateDateTime must be surrounded with a single quote.
In order to send the all the items at a time, use the action Create HTML table, then in the action Send an email, make sure enable Yes for the Is HTML field.
Please check the following screenshot for a reference.

More details about Odata filter query, please check the following doc:
https://docs.microsoft.com/en-us/previous-versions/dynamicsnav-2016/hh169248(v=nav.90)
More details on Workflow definition language, please check the following link:
https://docs.microsoft.com/en-us/azure/logic-apps/logic-apps-workflow-definition-language
Please feel free reply if you need more help.
Best regards,
Mabel Mao