This is the list I've been running for the pauper event. I've got 7 wins on 3 out of 4 runs with it.
The game plan is pretty simple: play a lot of grenadins and swing hard with Rally
. Recur Scrap Hound
, Ravenous Thornbeast
and Powderkeg Rider
to renew their abilities and make big units. Mulligan fairly aggressively for a turn one or two play.