Amazon has put up the product page for the digital versions of The Legend of Zelda: Breath of the Wild. If you are interested, you can reserve the latest Zelda installments with the following links: Nintendo Switch version and Nintendo Wii U version.
The physical versions of The Legend of Zelda: Breath of the Wild appear to be suffering from stock issues at major retailers, especially for the launch of the Nintendo Switch. So, if you are planning to get the game on launch day, then your best option may be going digital.
The aforementioned The Legend of Zelda: Breath of the Wild Expansion Pass comes with several in-game items, including three treasure chests that will be available right away. One of these chests contain a Nintendo Switch logo shirt while the other two houses useful items. The pass also has two content pack, the first of which (due to launch in the summer) adds a Cave of Trials challenge, hard mode and new in-game map feature. The second content pack, slated for Holiday 2017, includes a new dungeon, story as well as challenges.
The Legend of Zelda: Breath of the Wild launches for the Wii U and Switch on March 3rd.