Hey, thanks!
Lupine Prototype is pretty terrible by itself, but it is an artifact creature. Also, you can play it turn 2 and follow up with a turn 3
Tormented Thoughts, which is hilarious.
Tormented Thoughts is also from Origins though, so a better choice might be
Wild-Field Scarecrow.
Wild-Field Scarecrow has a way to sacrifice itself AND puts 2 land in your hand for 2 mana. Not too shabby.
Epitaph Golem is another option, but I'm not really a fan (There are better ways to pull stuff out of your graveyard). However
Epitaph Golem CAN survive
Languish, so there's something to be said for that.
Bottom line though, I say wait for the Kaladesh expansion to come out. I'm banking on there being more than a few decent Artifact Creatures that will provide a decent replacement for
Hangarback Walker. We've got some time before Origins drops out too, don't we? I think Dragons of Tarkir is next on the chopping block.