All except one can be printed in one piece and even better, they're all free. All you need to bring these models to life is a 3D printer and the files found ... Holes" under Mesh Fixes in Cura ...

and it’s a Python library to convert images or text to 3D-printable STL files. The examples shown are quite impressive, and it even does a top notch job of taking a 2D company logo into 3D!