which 3d software should i learn for 3d printing —

Founded which 3d software should i learn for 3d printing models & stl files for printing
Modular SnapFit Airship
RealAbsurdity
Ring sizer tool
Cloe_Fulk
Lampe  Fully 3D Printed Designer Lamp
Agustin 'Flowalistik' Arroyo
Table clamp
Josef Průša
Warning
Kenkay