You can buy most of these terrain pieces from manufacturers like GW or Armorcast. (I didn't sculpt it.) This gallery is here to show you a collection of well-painted, themed terrain, to encourage you to start your own collection!
These are the smaller three piles of skulls.
In the upper left, the rat is dragging away two rotting heads. In the lower left, another rat is looking at a rotting head and thinking the same thing. On the same piece, the head of a pitchfork is leaning against the tombstone, ready for a hand to reach out from the grave and grab it.
In the upper left, an arm is breaking up out of the ground, though it's hard to see in the photo. The skeleton rising from the ground on the upper right is from Reaper. In the lower right, two rats dig into the spilled guts of the torso of a hanged man. In the lower left, there's four heads on spikes, with some heads and skulls below them.
In the upper right is a rotting arm and a coffin lid, both by GW. In the lower left, there's another coffin lid but it's upright between tombstones so it's hard to make out. Another head-on-a-stick adorns the piece to the lower-right.
The last of the rows of graves. The tombstones are from Armorcast. I tried something new with the bases, mixing talus (irregular pieces of rock) to the sand, then painting the talus grey. It wasn't tedious and produced a rubble effect. The necropolis was looking too freshly-mown.
Here's another pic.
These six pillars are old lead Grenadier menhirs mounted on 25mm bases. While painting them, I discovered four of them had words on the side: sea, chaos, hill and dwarf. They apparently came with Giant figures and the words were for each kind of Giant.
I think these three pillars are from Reaper too. They have gargoyles atop pillars with skulls on the ground around them.
These two Reaper gargoyles are meant to be used as miniatures, but I liked them as statues. They're mounted on 50mm bases.
Here are three more pillars/statues. The ghostly one on the left is by Grenadier. The lizard-like one in the middle came from someone else's junk box when he sold his figs to me, so I don't know who made it. There's a snake crawling across the skulls on it. The cross to the right is actually the base of a Reaper figure.
This is just a back-shot of the same pieces.
This came from the same junk box as some other pieces. It's a big statue of death. I mounted it on it's own base since it's so heavy, and added some flock to make it look a little overgrown.
These were the first four pillars I made. I glued old D&D figures (probably Grenadier or Ral Partha) to the tops of wedding cake pillars. They're very top-heavy and prone to breaking.