Here's some free Xpresso setups for creating strobe, pulse, and flicker effects in Cinema 4D. While created with lights and luminous materials in mind, they can be used to add these effects to any parameter in Cinema 4D accessible via Xpresso.
There are separate scene files containing controls for each effect, plus another scene file that contains all of the effects in one controller with a combined output (see interface image below). These controller null objects can be added to any scene file, and all you'll have to do is double click the Xpresso tag on the null object to open the Xpresso interface, and then connect the green final output node to whatever parameter you'd like to apply the effect to. To access the controls, simply select the controller null object, and click the User Data field.
The controls are pretty self explanatory; a few minutes fiddling around should be all that's needed to figure them out.