There is this guy that made tons of D&D models for printing

https://www.shapeways.com/designer/mz4250/creations?s=0#more-products

I'm a programmer not a modeler or texturer or whatever it is called ... artist ...

Is it possible for someone to transform these printable monsters into gameplay monsters ? Would it be easy or take months for one creature ?

I'm curious

Converting them would be easy as described here.
creating textures for them is labour intensive though.

As another non-3D artist, I'm going to speculate that they're missing a lot of the rigging to do animations too.

I see, well doesn't sound hopeful yet. I had hoped to remake the sunless citadel adventure. A classic d&d adventure. However without twig blights the trademark creature of the adventure it will be hard to pull of. This guy actually made a twig blight model but I would need to learn how to import it in the game as a playable model and I'm not sure if it is feasible without spending a year on it ...

Wow man! I had the same idea!!! Remake the Sunless Citadel. Did you already start on it?