Where I live we have a thing called Chapel Hill Grit. It is red clay in color but similar to pea gravel in consistency and use. It does have some really big rocks that I pick out and use to fill ditches with.
In Europe I have seen them use pavers for their paddocks. Looks beautiful, but expensive!
Windward Farm, Washougal, WA- our work in progress, our money pit, our home!
Many folks use "hog fuel" up here--essentially very large bark dust (may contain small branches, wood chips and ground up bark). It is usually free, as the county goes around trimming trees and dumping it where people ask for it.
I've installed cedar hogs fuel, which is often used in indoor rings here, in my paddock as well. The only down sides: it must be replaced as it breaks down, which happens fast here in the wet. Doesn't drain, but does form a springy mat that can stay wet for days on end,underneath. Difficult to pick manure off with a fork, so I used the "glove and toss by hand" method, which is a bit time consuming but removing manure is so essential.
Horses LOVED it! Lots of happy rolling (I left a deeper pile just for that purpose) but in the end, I removed it all and put in gravel as the maintenance in our wet climate was just too much.
I did put down geotextile cloth first, so I have no mud with either footing.
Proud member of the "Don't rush to kill wildlife" clique!