ADRC is not a fixed set of equations and hence should not be viewed as a magical set of formulae that, once implemented on the real system, will do wonders. It should instead be understood as a modular, flexible framework that could be tailored to specific applications. This, however, requires a bit of a different mindset—one that is open to change. In this chapter, we show potential extensions and modifications to the ADRC scheme which take into account practical scenarios where certain actionable information is available about the governed system and/or acting disturbance. We also show how the performance of ADRC can be increased, for the price of additional tuning, by incorporating some nonlinear components. We will also introduce a so-called error-based variant of the ADRC scheme which is considered a bare-bones version and has some interesting practical characteristics.