There are 3 main categories in the freezer department and inside each you can narrow down the type you want to tailor exactly what you need.
Chest Freezers: Chest freezers are freezers that are shaped like a chest and offer large storage capacity. They differ from a normal freezer because instead of having a normal door that opens sideways, the door is attached to the top so opens by lifting upwards. They are normally wider than a standard freezer, but due to the door positioning are also shorter.
Upright Freezers: These are all freestanding machines. These consist of either undercouter machines (normally 85cm high which are designed to stand under a kitchen worktop) or upright freestanding machines which are built to stand on their own (without the need to be built-in to a cupboard) and can be anywhere up to around 200cm high.
Integrated Freezers: These are freezers that are specifically made to be built in to a kitchen unit and can't be left as freestanding. They come as either undercounter units (made to be built under a kitchen counter) or tall freezer appliances (which are made to stand specifically in a kitchen cupboard). Once built in they will have your own cupboard door attached to it so this will maintain the kitchens overall style and design.