From what I understand, the A/DA Flanger has an expression pedal input that lets you sweep the flange with the pedal, like a wah or the Tycobrahe flanger. The Mutron Flanger also does this. I haven't finished my A/DA yet though so I can't confirm. The EHX Electric Mistress also does this in Filter Matrix mode, but there's no expression pedal input for some stupid reason.