Concerta and Ritalin contain the same active ingredient, methylphenidate. Both may come as extended-release tablets but Concerta is harder to abuse because the XR mechanism is harder to bypass. Basically Concerta tablets are hard as a fucking rock while Ritalin XR capsules contain waxy beads that are much easier to crush.
Adderall contains mixed amphetamine isomers and salts, it is a more potent stimulant than methylphenidate.