A deck designed to get ALL THE RATS EVER with Coldsnap's Thrumming Stone. An easy turn six win for a relatively cheap price (especially in modern). This deck also has 2 copies of Pack Rat that will be a similar size to relentless rats. 2 Go for the Throat, 2 Doom Blade, and 1 Hero's Downfall are the removal suite for the deck (Hero's Downfall can easily be switched out for a Murder if Liliana isn't a problem in your meta. Unmake is another acceptable replacement.). We have 2 Immortal Servitude that, for 6 mana, returns ALL of our Rats from the yard. The rest is Rats. We have extra removal in the sideboard, mainly for Abzan, Delver, and other creature heavy decks. We have a Dash Hopes in board to either shoot our opponent for 5 or counter a good spell. We also have low-scale ramp to get rats out faster when against grindy matchup.
The ideal play: T1 swamp
T2 swamp pack rat
T3 swamp relentless rats
T4 swamp relentless rats
T5 swamp Thrumming Stone
T6 swamp relentless rats (stone triggers for rest of relentless rats) swing for lethal.