Find emails with a specific subject or from a particular Sender
There are multiple ways to search for an email within your Gmail account. Most users would normally utilise the search bar at the top of the page. The problem with this method is that the results will also include, unless specified, conversations from Chat.
A quick way to find all the emails with the same subject, unless you haven’t already enabled Conversation View, is to right-click on an email and then select 'Find emails with this subject'. Gmail will now show you both the received and sent emails with the same topic.
Using a similar approach, you can also find emails from the same sender. To do so, right-click on the email and then select 'Find emails from ...' This method will show you only the received emails from a specific contact.