@Flash525
There are about as many things that you can print as those that you can't!
Ultimately it is all about the effective resolution of the printer.
If my memory serves, on an
FDM type 3D printer it is possible to go as small as a 0.2mm extrusion nozzle and 0.1mm layers.
However, the trade off is that the thinner the material and the more layers there are, the longer it takes to print.
The scourge of 3D printers, in my opinion are overhangs. If an overhang angle is too high, then the print will fail as it tries to lay down layers in mid air! Of course it is possible to generate supports, but this will use more filament and extend the printing time further.
If you are going to upscale your miniatures to 6-7 inches then I think you should be able to print these quite well.
But be prepared to set aside a lot of time learning how to set up your printer and spend frequent amounts of time physically maintaining it too...
Ultimately, it is a fun and sometimes practical thing to have in your arsenal if you are a hobbyist.
FWIW... I think the best 3D printers are the
resin based type. If I ever have any spare money, I will get one.
If you do decide to get one, I recommend that you ensure you have a build surface with an X/Y axis of at least 250mm and a Z axis of at least 200mm.
In closing I will say that what I have learned owning and using a 3D printer is to have patience and expect things to go wrong more often that you would like or indeed expect. And that 3D printing is definitely more of an art than a science...