All Google docs, sheets and slides are listed on the Drive Home page - with an indicator showing the document type e.g. document, presentation, spreadsheet, form, etc. The document name will show, along with the owner of the document and the date on which it was last modified. 

Quick Access uses machine learning to intelligently predict the files you need in Drive, and places these at the top of your Drive list for easy access. Quick Access uses information such as who files are frequently shared with, when specific meetings occur and what files are used at certain times of the day to suggest the files you will need each time you access Drive. 

To open a document from the Quick Access pane, double-click on the document

To open a sheet, double-click on the name of a sheet on the Drive home page. The sheet will open in a new tab or window, depending on your browser. 

To open a sheet from within another doc, sheet or slide:

To view all types of files, regardless of the app from which you chose the Open command, click on the X next to the filter in the Search box.