I am planning to make own drone which flies and dives (Some servo motors used to change between fly and dive-mode). But is a normal DC motor or a micro motor good enough (It flies and dives under tens of meters happily.), or are special motors needed for diving and flying. And what would be the lowest rpm and/or torque? So the drone would not be very big or heavy (something like here? https://www.thingiverse.com/search?q=drone&page=1&type=things&sort=relevant) it's 3D printable.
It is just about possible to make a quadcopter fly with brushed DC motors, but almost no one uses them. They are heavy and need to be run pretty hard, which wears out the brushes in a few hours. Generally you'll only see them on cheap toys, and then they're probably geared to use large props for very low performance.
If you want a cheap motor with reasonable performance as a starting point for designing the rest of the drone, I suggest the Racestar 2205 with 5" props, at least 30amp ESCs, and a 1500mAh 4s battery. That was a pretty standard 'freestyle FPV' build about 5 years ago, and pretty cheap now.
If you want to see what's popular now, I recommend http://fpvKnowItAll.com