Digging shovels are built with a slightly curved scoop and upturned edges. The blade edge can built with either a pointed or flat tip.
Drain spades are built with very narrow with slightly curved sides. The blade edge is built with a rounded tip.
Roofer's spades are built with steel strapping that provides a fulcrum for the tool head which facilitates the prying off of old shingles from the roof. The blade edge is often sharp...
Snow shovels are built with a half cylindrical wide "Scoop." The blade edge can be built with either a sharp or dull edging.
Scoop shovels are built with a broad and wide-flared "Scoop." The blade edge is dull with a flat tip.
Trenching shovels are built with squared sides to produce clean trench walls. The blade edge is sharp and pointed.