Here is DC Motor working principle; types of DC Motor - Brushed, Brushless, DC Servo Motor; DC Motor driving using H bridge and L293D motor drivers, etc.
Is there a way to tell whether a DC motor is brushed or brushless? - Electrical Engineering Stack Exchange
Brushless motors Powerful with long service life
DC Servo Motors How it works, Application & Advantages
The Complete Servo Motor Guide
Which types of DC motors can be used as servo motors?
Brushless Servo Motors and Brushed Motors: Which to Choose
Brushless motor vs brushed motor: The features of the Orbray brushless motor. - Orbray MAGAZINE - Orbray Co., Ltd.
DC Motor Types - Brushed, Brushless and DC Servo Motor
Brushed vs Brushless DC Motors: Which is Best for your Application? - Tech Briefs
What is brushless motor?
BLDC & AC servo motors w/ encoders, NEMA 23 & 34
What is a brushless DC motor? What is the difference between brushless motor and brushed motor?