Reaktor/Tutorials/Reaktor as effects processor/The difference between effects and sound sources
The difference between effects and sound sources edit
Effects have audio inputs and outputs. Sound sources (synths, samplers, loopers, drum machines, etc.) only have audio outs. Effects are usually labeled as such in R library folders, the user library, and other online sources.
I've created an FX Favorites folder and made that a favorite in the Browser, so whenever I open a new effect and like it, I've got a place to save a copy of it, including any new snaps I've created for it, and any other changes I've made to the file. I usually use its original name, so I can track that down if necessary, perhaps with some additional info to distinguish it from the unchanged version.