Most toys from Tantus are fine for anal play. They have a nice base and varying sizes.
We use the Marble G Slim Line vibe for anal play, but we only use the ball on the end and he always has a full fist hold on the handle of the toy. (We also never turn it on, as it's so loud. But, the same company makes a gray anal probe which is identical. It's long enough to not worry about "losing" it.)