A pitched (i.e. very short) delay effect, with a pattern sequencer to control it. Not the most useful plugin, but you might find a place for it if you like weird electronic noises.
free vst plugin. pc
Duckdelay: this is a delay whose output is compressed when there is a certain amount of signal present on its input. It allows to use a lot of delay on a voice without loosing too much intelligibility.
free vst plugin. pc.
Octodel: 8 simple echoes in line.
8 single echo in line with volume and stereo fully controlable for each echo....
Full C++ but no SSE used so it works on any CPU.
But still very low CPU usage: 1,8% on my XP2600.
Sliders are volumes, knobs are pans...
I think it does not require any other explainations....
It's very easy to use...