This article is from the Recreational Figure Skating FAQ, by Karen Bryden with numerous contributions by others.
There are four kinds of figure blades:
-- Freestyle, which have large toepicks for jumps, deep grind so you
won't skid and less rocker for more acceleration.
-- Patch or figure, which have the shallowest grind for maximum glide
and tiny toepicks (only used for pushes and stops). Since the removal
of figures from eligible competitions, most blade manufacturers have
discontinued figure blades. It is possible to transform a normal
freestyle blade into a patch blade by regrinding the hollow to about
1'' radius and shaving off the lowest toepick.
-- Dance, which are shorter blades so you won't step on your own or
your partner's blades. Compared to freestyle, they have smaller
toepicks, and more rocker to make turns easier. They are also narrower
and a deeper grind, to allow deeper edges.
-- Precision or synchronized skating blades, which are also shorter
than freestyle blades.