Chorus
The chorus effect modulates the original sound by a sinusoid low frequency oscillator (LFO). The output sounds like there are multiple sources emitting the same sound with slight variations - resembling a choir.
You can tweak the chorus filter to create a flanger effect by lowering the feedback and decreasing the delay, as the flanger is a variant of the chorus.
Creating a simple, dry echo is done by setting Rate and Depth to 0 and tweaking the mixes and Delay