I am especially interested in gumi futanari but all is welcome
I might be tag searching wrong, but this seems to be the closest thing to gumi futanari I can find on pixiv.
There is an abundant supply of miku dicku on pixiv, however.
That pic and this one are the only ones I could find on Pixiv.
And I used every combination I could think of.
The four tags for Gumi:
GUMI, グミ MEGPOID, メグッポイド
And the Futa tags, the main one and the lesser used tag:
OP is going to have to try the drawthreads for any more Gumi futa it looks like.