This is a re-upload of R2 Through R9 Astromech Droids (not Lego). I added a render for the cover picture. All parts should print fine on most printers, but the legs may need to be reoriented. If you are familiar with the R series droids then the picture will make perfect sense, if not, I can give you a little help.

Starting on the right, we have the ever popular R2 droid, it was very versatile and loyal.
Next we have the R3 droid popular on larger capital ships or in illegal use in rebellions, it usually had a clear plastic dome unsuited for outdoor use.
The third from the right is the R4, an extremely popular droid among smugglers and other illegal trades because of its low price and high functionality, though not quite as powerful as the R2 or R3 model.
After the R4 is the R5, another cheap droid, but this time they cut too many corners and made a fairly poor quality droid, we see this issue onscreen in episode 4 when a perfectly fine R5 spontaneously breaks.
After the disaster of the R5, Industrial Automaton had to save face. The R6 brought back the high quality that had been absent since the R2 and added more features, the final result was actually cheaper than the R2 when it was new.
When a new war started a new droid was needed to help pilot the complicated E-wings, thus the R7 was born.
After the E-wings became outdated a new droid was made with massive compatibility: the R8.
Finally, on the left is the R9 the last known R series droid made by Industrial Automaton. The R9 had more features than any previous model, but had a really strong self preservation program that ended up causing trouble for some owners.

I tried to make the colors in the render match colors of existent droids. I recommend the colors shown in the render if you have them, however, feel free to get creative and print in any color you wish.

As always guys and gals, happy printing.