Motor Shield Standard
A4988, DRV8825, what else can you put on a blank template that fits on the Pololu type interface?
The board is 15.2x20.3mm, 0.6x0.8"  pololu.com
The A4988 chip is 5x5mm with about 1mm height
The DRV8825 chip is 6.9x10.2mm datasheet
== Headers, voltage, ampage ==
You should pay attention to the maximum voltage and ampage that can be transmitted through headers, refer to the specific datasheet. A given maximum of 3A is equal to certain types of stepper motor bigger than NEMA_17 form factor. Certainly to run any type of big DC motor, for ie. a filament extruder, you may want to do away with these headers and try to find ways to work on the bare electronics PCB.
Tha author would like to have a 3.3V voltage adapter soldered in so that the pins can be used to power a 3.3V DC motor.
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