dregscape sliver + basal sliver = "Exile a sliver you control: Return a sliver from your graveyard to the battlefield."
If you start with 4 mana available (possible via gemhide sliver) and two slivers on the battlefield, you can go:
Unearth Dregscape
Unearth Basal
Sacrifice a sliver for BB, unearth Lavabelly
Sacrifice a sliver for BB, unearth [any random sliver], ping for 1
Sacrifice the sliver you just got, get another one, ping for 1
And so on. The only difficulty is putting enough slivers in your yard in the first place.
maybe puts some juice back into Thopter/Sword; if you get the combo going with Urza out you win on the spot (or, at least, you get to put your whole deck on the battlefield)
If you start with 4 mana available (possible via gemhide sliver) and two slivers on the battlefield, you can go:
Unearth Dregscape
Unearth Basal
Sacrifice a sliver for BB, unearth Lavabelly
Sacrifice a sliver for BB, unearth [any random sliver], ping for 1
Sacrifice the sliver you just got, get another one, ping for 1
And so on. The only difficulty is putting enough slivers in your yard in the first place.