Change the Number of Recent Documents
The goal of this tutorial is: change how many documents are shown in the Recent Document List.
You can increase the Recent Documents List (located at Office button menu, see figure below) to your desired number of workbooks, you can select 0 to 50 numbers.

Go to Office button > Excel Options > Advanced, scroll down to the Display options and change the value of Change this number of Recent Documents drop down as shown in figure below.

Note: Fewer documents will be visible if the list does not fit on the screen.
MS Excel