In https://www.printables.com/model/426277 I provided automatically converted LDraw.org parts. While they provide thousands of parts they are mostly designed for rendering and not for printing most of those parts are not manifold and thus may produce unexpected results when slicing.

In an OpenSource effort at https://github.com/schiele/soLDraw I started a library of solid counterparts to LDraw parts that reflect the same shape but are remodeled to be manifold and thus can be correctly processed by a slicer and then easily printed. Depending on the part's shape, you might still need support material for proper printing. Feel free to contribute additional parts or fix bugs through a pull request on the GitHub project.

Since the design is based on the LDraw.org parts library, this library comes with the same license terms. You can find the complete original library at https://library.ldraw.org/updates

With the latest versions most parts were drastically optimized for FDM printing, retaining the original visual appearance wherever possible. I printed the whole sample car model from the LDraw library except the tires since I didn't have TPU available when printing. The model for the tires is included though. Note that some parts are very fine-granular, too much for an FDM printer with a 0.4mm nozzle to handle with the same precision you would see with the injection-molded parts you can buy in the toy shops. That means in the model it is unlikely that the wheels are turning or the hinges open easily. This might work if you scale up the parts in a significant way. If you just want to play, the original parts from the toy shops provide more fun but if you quickly want to get some missing parts or just for the sake of enjoying the possibility of doing it yourself printing them with those models is a way to go.

Update: Added 3mf files for car model for easier printing on different printers.