random prim STUFF. - prim types

There are 20 prim shapes available for use under the Object tab of the Build Menu. ( 22 on Firestorm's build menu list; Sculpted Prims & Circle->Half-Circle are purposefully excluded here. )
I've grouped them according to the parameters that affect them.

regular shapes

developmental shapes

Basic

Cube/BoxCylinderPrism

Sphere*

Sphere

Curved*

TorusTubeRing

Circle2

Circle2->SquareCircle2->TriangleCircle2->Circle*Circle2->Half-Circle

Test

Test->SquareTest->TriangleTest->CircleTest->Half-Circle

33*

33->Circle33->Square33->Triangle33->Half-Circle

Line

follows basic params, except for LSL & Taper.

Line->Half-Circle

*Sphere, Curved, and 33 Shapes respond to parameters very similarly, and are mostly interchangeable. They have different limits & topology.

*Circle2->Circle technically reverts to Sphere when selected, but will visually remain as a Circle2 shape.

Exploitable parameters are achieved by changing the values via another shape, one with greater possible values, and then swapping to the exploitable shape.ex;
33 shapes have a taper limit of
| 0.0, 2.0 |spheres have a taper limit of
| 0.0, 1.0 | but can be exploited to 2.0

Some parameters rely on, or change others
Skew & Revolutions
Taper, Taper Profile & Radius
Taper & Top Shear

Names of parameters change depending on the shape
Taper = Hole Size
Profile Cut = Dimple = Slice

Some of the shapes that are visually indistinguishable sometimes have different UV mappings.
Also, depending on the Hollow Shape used, Topology & UVs may also change. This probably isn't all of them, but just to give you an idea here are the ones I personally use often.