Rat Plague (Rat Tribal) (Modern) [Revision 11]

First of all: Lurrus is NOT a part of the actual strategy. It just was a free companion and had a bit of synergy with Pack Rat as it can reanimate our discarded permanents.

We are playing a quite aggressive gameplan. We want to get as many rats out as possible growing our Pack Rat and Rat Colony bigger and bigger each turn. Piper of the Swarm also provides token generation but more importanty evasion with menace.
We literally play every one drop rat (except changelings) available in modern, as their abilities are not really important for us, we just want more rats out for Rat Colony and Pack Rat.
Board wipes are our nemesis as we can't really recover from them and really rely on the quantity of creatures on board (not to mention Plague Engineer). But we run Swarmyard so we can at least save one of our rats from board wipes.
The discarding ability of Pack Rat can also be pretty powerful in the late game, growing other rats even further.
As we have to discard for this ability we have plenty of card draw with Sign in Blood and Castle Locthwain.
We have some removal ourselves with Doom Blade and Go for the Throat to deal with early threats when our rats are not big enough to deal with them.
If the opponent does not play mass removal we have a good chance of winning because with Piper of the Swarm our Colonies and Pack Rats are hard to block and become just eldrazi-like-gigantic over the course of the game.