Hi @BKGOUD ,
Do you want to fire your flow only once time, and then send an email including multiple records details?
Based on the needs that you mentioned, I agree with your solution. I think two Lists could achieve your needs. On your side, you just need to set up a flow based on your second list using "When an item is created" trigger of SharePoint connector.
Then retrieve related records from your first List based on the common Id value (using "Get items" action). After that, you could convert the retrieved results into a HTML table, then embed the HTML Table into your email body.
I have made a test on my side, please consider take a try with the following workaround:


Within the "Filter array" action, click "Edit in advanced mode", type the following expression:
@equals(item()?['Id'], triggerBody()?['Id'])
Note: The Id represents the common id value that you mentioned in your First List and Second List. On your side, you should replace it with actual field name from your First List and Second List. The format as below:
@equals(item()?['IdColumnInFirstList'], triggerBody()?['IdColumnInSecondList'])
Please take a try with above solution, check if the issue is solved.
Best regards,