Here’s the totally unique MSK007 Leapfrog VCF (voltage controlled filter) from North Coast Synthesis. It’s a “near elliptic musical low pass filter”. I can’t think of any other elliptic filter in the format or other formats but I’ve linked to some information below. It’s basically a very very steep cut off that gives a unique character, saturation, resonance due to this unique curve that isn’t from something we’re used to. To my ear it’s got a rubbery, vocal like character and it takes to modulation really well.

https://northcoastsynthesis.com
https://en.wikipedia.org/wiki/Leapfrog_filter