A grid mode is available as an alternative view for the documents where they are displayed in thumbnails.
Adobe Acrobat Reader comes with a text highlighter.
The default color is bright yellow.
The color of each highlighted color can be changed individually, which comes useful in organizing and searching notes.
A sticky note or comment can be added to specific text or page in a PDF file.
The note color is adjustable too.
It is large in size and slower to load than free alternatives such as Sumatra PDF Reader.
