I've made a lot of 3D dice, and I've had quite a few output on 3D printers. Some of the shapes are easy to make with simple object primitives, but the one that takes a few steps to get started is the d10. It's still pretty easy.
1. First, make a Cone object primitive in the Top viewport. Radius 1: 20, Radius 2: 0, Height: 20, Height Segments: 1, Cap Segments: 1, Sides:5 and uncheck Smooth.
2. In a side viewport (left, right, front, back, but not top, bottom, or perspective) restrict to the Y axis and move it up a bit, then hit the Mirror Selected Object(s) button and choose XY and Copy.
3. Restrict to Y-axis and move the bottom one down a little. Again, this is in a side viewport, not perspective, top, or bottom. Don't move it too far from the other one.
4. Select each of the two pseudo-cones separately and click on the Edit Stack button to Convert To: Editable Mesh. You could also just right-click on the name of the object in the list in the Modify Panel and choose Editable Mesh.
5. In the Perspective viewport, go into Polygon Sub-Object editing mode and select the flat bottom (or top in the case of the mirrored clone) and delete it. Then turn off Sub-Object and do the other.
6. With one of the two selected, click on Attach and select the other one. Now they're part of the same object. Now turn off Attach.
7. In Element sub-object mode, select only one of the two pseudo-cones and use the Select and Rotate tool. On the slider at the bottom rotate it 180 degrees in the Z axis. It will look fine from the Top view, but crooked from the sides. Don't worry. That's the way it's supposed to look.
8. Go into Face Sub-object mode.Turn on Create. Create triangular faces by clicking vertices going counter-clockwise for each so the normals face outward. Start in the Top view to make it easier. Then continue in Left and Right views until each triangular face is extended into a kite shape.
9. If you want to take off the sharp top and bottom points (in case you walk barefoot and one ends up on the floor) you can use the Slice Plane button. Move the plane to the desired line where you want to slice it off, then click Slice with the Split option checked. Do this again for the other end. You'll have two new pieces on the ends. Delete them and then go into Face sub-object mode and Create new faces to fill the two holes.
10. If you want it to look like a die that's been through a rock tumbler to take off the paint that goes into the number recesses, get out of Sub-Object mode and add the MeshSmooth modifier to the stack. Choose Classic as the type. Set Smoothness to 1, and the Strength very low, around 0.1 to 0.16, but experiment. Operate on quads, not triangles. Turn off edged faces for the viewport for a better idea of what this looks like.
Adding the numbers can be done in several different ways. If all you needed was to 3D print a blank die you can write on with a Sharpie, you're already there. Otherwise the numbering is a pretty involved and time-consuming process. I've spent many hours in the battle of the booleans to get mine right. There are millions of possible options for making the numbering and otherwise modifying the shapes of your dice, but this little tutorial will get the basic shape of the d10 out of the way for you.
If you just need dice for a realtime renderer or animation instead of 3D printing, the standard methods of using unwrapped textures and bump maps work fine. For output with a 3D printer, everything needs to be modeled and the final version needs to pass STL checks before you send it for printing.
For other types of dice, remember that the Geosphere object primitive is your friend.