Types of Laptop Bags
Conventional Hand/Shoulder Bag (Messenger Bag):

This is the most common type of bag you will see. There is usually a hand grip at the top for carrying it that way, and a shoulder strap that allows you to adjust the height to what’s comfortable for you.
Backpack:

This is the second most common bag we tend to see purchased. This is my personal preference as it is most comfortable for me personally. The bag is usually packed at the very back of the backpack, so it will be right against your back as you are walking for maximum protection. The upside to having one of these types of bags is you can also store a good amount of books along with your bag. If you are in college or high school this would be the type of bag for you.
Sleeve:

This is debatable whether it is a bag or not, but it definitely is a form of laptop protection and we appreciate these very much. This is the type of bag that will allow for the lightest weight possible to protect your laptop. It wont protect against much damage other than scratching all by itself, but it can very easily fit in a second bag for travels.
Those are the primary types of laptop bags that you will find when in the market for purchasing. I hope now you are more informed on what you will be looking for when making your decision!