Plugins that make Reptopolgy easier

Here is a list of most of the better add ons.  Notice decimate is the first one and is included with blender and simply reduces the amount of polys in the mesh. (Very useful)

Good reference of dinosaurs running.

Nice walk and roar, if you rig your lizard well, you can do this type of animation.

Blender has a benchmark page, and there are numbers all over the place, you can't tell what's a real benchmark.

These videos show people rendering using a 3070 etc., and you can see how long. 

Inspiration

This guys planets look awesome.  Sam Krug  He has some details on how he did these in blender also.