There are lots of utilities that are needed in most (if not all) FTC robots' code. Lots of these are wrapper classes for the raw hardware classes (e.g. a CachedMotor wrapping the DcMotor class).
More will be added to this list later, and this is not an exhaustive list.
Cached Motor
Cached motors wrap DcMotor/DcMotorExs. These save the current direction, speed, and/or other properties of the motor. You could also build a StatedMotor on top of this that saves the state of the motor, but this is not always necessary and could just be unneeded code that serves no purpose. You can read more about these in 1410 Cached Motors.