Plug-Ins:

Real Player is having different variety of plug-ins.some are,

Audio Enhancement :
There are four audio enhancers in the latest version of RealPlayer they are DFX,iQfx,Volume Logic and Sanyo 3D Surround.

RealPlayer Skin Creators :
SkinsEditor for RealJukebox(which allows users to organise their digital music) and RealJukebox Skins Converter, which converts Winamp skins into RealPlayer skins.

Radio Tuners:
vTuner Plus and HMRadio are radio tuners created for RealPlayer

Visualizations:
visualizations that are from the RealNetworks site are: FrequencywurX, FyrewurX, FlamewurX, XFactor, Spectrl View,FluxWave, Puddle, Paint Drops, Polka dots, StickSterZ 1.0, Circle, On the road, Real Logo, Hubble Bubble.