I've been plugging in my Shield Tablet to my computer with a 3.5mm to 1/4" adaptor cable, my Nanoverb, and an Lexicon Alpha. Works fine for me.
As far as apps go, I've been using PicoPico, DRC, and ExSynth. Virtual ANS is interesting but hard to figure out how to use.
I wish Animoog would get ported over. Finding out that it wasn't available for Android inspired me to make this topic.