i just uploaded my first external to deken called simplex~. it's an object that allows you to sample simplex noise with multichannel signal input from 1 up to 4 dimensions. i'm pasting a screenshot of the help file here to give you a better idea. one rather simple application that i worked with quite a lot during the last months is a variation of scanned synthesis, where the 3d noise space is sampled in a spiral movement. you can also see and hear this (and change a few parameters) in the help file.

besides that, there are probably a lot more applications for this type of noise in Pd. looking forward to exploring them and happy about any kind of feedback or other demos!