[jcelerier]

you can do that trivially with sox (http://sox.sourceforge.net/sox.html)

    alias fx="sox - -t wav -"
    cat foo.wav | fx overdrive | fx reverb | play -

considering that sox has existed since the early 1990's, I'd wager that the demand for that isn't exactly huge

(note that in practice you'd directly use sox's play command to apply effects as it's certainly muuuuuuuuuuuch more efficient than to spin up a ton of processes which'll read from stdin/stdout)

[dimatura]

I've never actually used sox for fx, I wonder how good they are. (I have used it plenty for resampling, normalization, trimming, etc). But regardless, there's thousands of VSTs out there -- a lot more options than whatever sox has built in.

[jcelerier]

IIRC Sox can apply plugins, maybe not vst but lv2 or ladspa

[xorcist]

sox filters are generally high quality, they weren't designed to run in real time.