Depending on the type of work you do, mousing may feature prominently in your day. The positioning of a standard flat mouse puts the forearm in a rather extreme range of rotation and over time can cause to a longer chain of the upper arm and shoulder rolling in as well. Using a vertical mouse set on a pad slightly outside your shoulder width will help to allow for space in the shoulder girdle through your day and ultimately help to evoke a more neutral shoulder rotation and more access to upright posturing. I especially recommend considering getting a vertical mouse if you are typically using the touchpad and the center of your laptop for mousing.
The Evoluent Vertical Mouse is probably the first vertical mouse I recall using and has continued to be a mainstay of my recommendations. It provides a nice neutral grip size and wrist orientation and allows for adapting the mouse sensitivity on the fly, which is a great tool to have when you're getting used to a new hand position. It's a good size as well for the majority of hands I encounter and a particular bonus, it comes in left and right handed styles. You can find it in wireless and some variations with extra bells and whistles but I tend to prefer wired simply to avoid replacing batteries and such. In general, this is the first mouse I'll hand people to try out using and it's where I recommend starting if you're considering a vertical mouse.
Right Handed Mouse Left Handed Mouse
The 3M Vertical Mouse is the mouse I personally use at my office and at home. The 3M Vertical Mouse resembles more of a joystick but it simply allows you to hold the shape like a handle and move the entire apparatus around your desk. For me, this mouse is what has best fit the sizing of my hands, and the handle shape allows for a relaxed fit and ease of use that makes it the best fit for my day where I am shifting back and forth from mouse to keyboard to other work rapidly. The 3M Vertical Mouse also features a thumb-operated left and right click rocker button at the top which I find can be a little clumsy for things like drawing programs or drag and drop but which works great for me for single click operations like web browsing. If you have bigger hands, this tends to be where I recommend starting.
The Anker series of vertical mice is my starter recommendation for folks with smaller hands or for whom a fully vertical hand position might be uncomfortable. It features something closer to a 50-60 degree angle instead of a near-90 degree angle to the desktop and conforms nicely to medium-smaller hands for a relaxed position and a little more space to rest the hand across. It's also a particularly compact feeling mouse which makes it nicer for travelling situations and the like.