Do you have more than one PST file? And it takes you more time to check each PST file. Because of this, you want to merge all PST files. If you are looking for a good tool to merge PST files. So you can use MailsDaddy PST Merge and join tool. It is very easy to use this tool. Which merges multiple PST files in just a few clicks. This tool supports both ANSI and Unicode PST formats. And also supports all MS Outlook versions.
https://www.mailsdaddy.com/pst-merge-and-join/
https://www.mailsdaddy.com/blogs/manual-trick-combine-multiple-pst-files-single-pst-file/