I think this is a nice deck but I would add Gray Merchant of Asphodel . It would be helpful because of the massive devotion the Relentless Rats give you. Also when used with Doubling Chant it will most likely do 12+ damage. When I pull a Gray Merchant of Asphodel in my deck, A Truly Relentless Rat Deck, I usually win the game after following it up with a Doubling Chant . Also maybe some Elvish Mystic s to get Bloodbond March out earlier.

Stampede or Overwhelming Stampede .

megamastergamer I thank you for your suggestions. Here are my thoughts though and the general direction in which I am attempting to take this deck.Gray Merchant of Asphodel as I think the direct damage part is a good idea. My only problem with it is that it goes against the rats only theme Im trying to do. Elvish Mystic is pointless in this deck because of the dual lands. Stampede is not legal in the modern tournaments I am considering running this deck in. I like Overwhelming Stampede but in its place I am actually looking for something that would give all my rats swamp walk.

Maybe you can use Glaring Spotlight since it gives your creatures unblockable, also you can place it on your first turn so you can use it later.

Maybe but I got 2 copies of Urborg, Tomb of Yawgmoth chilling in my binder that I would like to use in this but I am not going to put them in needlessly. Swampwalk however would make them worth it.

I checked all over the gatherer and there is no card that gives all creatures swampwalk. The closest I could find for a low mana cost was Nighthaze .

What about giving them all intimidate?

To give all your Relentless Rats intimidate use Hideous Visage .

If you're willing to go for intimidate/fear (which is essentially the same thing since all your rats are black), you could add Marrow-Gnawer to give all your rats fear and have the potential to superpump the Pack Rat s. Otherwise, the only things I can find that can give all your rats swampwalk are Filth , which isn't modern, and Concerted Effort which is off-color and requires some shenanigans with something like Nighthaze .

Separately, you could pump all your Relentless Rats at once with Echoing Courage , which could be fun.

If you're willing to go for intimidate/fear (which is essentially the same thing since all your rats are black), you could add Marrow-Gnawer to give all your rats fear and have the potential to superpump the Pack Rat s. Otherwise, the only things I can find that can give all your rats swampwalk are Filth , which isn't modern, and Concerted Effort which is off-color and requires some shenanigans with something like Nighthaze .

Separately, you could pump all your Relentless Rats at once with Echoing Courage , which could be fun.

I think it would insane if you could squeeze Whip of Erebos in here for massive life gain and potential to bring back a Pack Rat to make a token again (but very expensive to do so) or even combo that with Marrow-Gnawer to make more tokens if you added him.