Carrier Snails

A few of the Feywild and Elves of Alfheim use giant snails in place of other animals to carry goods. Though slower moving than most, their shell provides a greater surface area for attaching goods and for protection of the animal itself.
Rarely seen outside of the Feywild & Alfheim, carrier snails are used in the latter two regularly in place of horses. With the elves the Wood Elves would use them much more commonly than any other. This is in part with them living in wooded areas that make keeping horses awkward at times due to the need for space and the snails ability to climb in some circumstances. Also, snails will feed on the detritus of trees and other plant material while horses have more stricter diets. Many of the 'Little People' such as Pixies & Fairies use them too, also breeding them & maintaining their health. A few minor strains have been bred over the years but outside the communities that use them can tell the difference.
A few humans use carrier snails too, usually in out of the way places & no access to horses. In every instance the shells will be modified during the growth of the snail to allow goods to be strapped to it. Rope hooks and special leather straps are used to hold the goods in place and most handlers are trained to pack & unpack the goods to spread the load and stop objects falling off. The snails are trained with specific codewords & staffs to get them to move, to stay still & to stay within a certain area. They are also trained to not damage or try to leave when packing & unpacking takes place. It does become quite a spectacle when a caravan of these come into town in the Material Plane as well.

Propulsion

Giant snails have a large pseudopod on them that they use for movement, and will produce a mucus layer to help with travel. A rippling effect causes the snail to move in a particular direction.

Armor and defense

As snails they have a gigantic shell they can retreat into if attacked. Slashing & piercing attacks are not that great against the shell with bludgeoning attacks can do better, the thickness of the shells can take a bit of work to get through on.

"Strange things those. Seen a caravan arrive here in Eschbach once. Came in from the other side of the western Grove. A bunch of Elves, pixies & fairies. They were selling all this strange silken clothing nobody could afford. They had got word that the village was going to be well-off at some stage and wanted to get ahead of the competition. They're due back some day."
Meaven of the Eschbach council talking to Lord Fyrwin.