Rythmic Robot have just released the 8th in their NanoMod series of cheap and cheerful Kontakt instruments. All are just £3.
 

NanoMod FM takes you back into the bright, shiny heartland of the 80s with two waves from Yamaha’s ubiquitous DX series. With their glassy, glossy digital sheen and metallic overtones, these are great for bells, bars and tines on the one hand, and richly-overtoned digital synth tones on the other. Tame them with the analogue Grit Filter, or let them shine through!

 
One good thing about this series are the relatively simple controls that make quite a bit of sound variation. On this one for instance MIDI control of the wave blend and smooth filter can be quite effective.
The only other one I have is the free NanoMod 7 8-Bit. On the strength of these I may pick up a few more at some time.

#8 is the best one yet. Most of the others are too lo-fi for my taste, but #8 is easily worth the £3 (~5 bucks).
 
[UPDATE]
Got it, playing with it now. I was surprised to find 9 instruments in there, all nice-sounding and most will be usable. Especially the first one, "RR NanoMod 8 FM.nki", a distorted organ-ish sound with a cool pluck attack.
 
What you've basically got are two waveforms, one more or less percussive and the other pad-like, which is looped for infinite sustain. You can then set the relative levels and tone of each of these components, plus the overall envelope, to get percussive or smooth sounds or variations in between. Kontakt's built-in saturator, distortion, convolution, delay, reverb and chorus effects are controlled by the UI knobs. The instruments are open for tweaking, so you also have the option of adding, say, a flanger if you want.