We used to call those signs in the following names :

Popular style, and the surface is flat with fabricated edges,  can be added lights and painted .

channel letters

channel letters

 

 

 

 

 

 

 

 

 

 

3D signs:  the surface is prismatic ,  man-made, expensive 

Can add lights and painted.

3d signs

3d signs

 

 

 

 

 

 

 

 

 

 

Flat cut  (Solid letters) :  thinkness from 1 mm,  can be sticked on glass, wall ,door  etc

flat cut signs

flat cut signs

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

By knowing this knowledge, you will know what exactly suits for you.