Rats. I've been there done that. But it just didn't really work for me, so I'm taking another crack at it.
I won't go for hand control, but instead focus on board control with kill-commands like Tragic Slip.
I've also added more hand control with Altar's reap and Sign in blood.
There might be too much regeneration in the deck, but I feel like I also makes me able to focus more on pack rats while still being able to field said rats from the graveyard.
Whip + Coat is my go-to comb. with these types of decks. You could argue that you could throw in a Akroma's Memorial, buuut it's just not a ratty card; I mean.. flying rats? No sir, no Covid here.
Other than that it's your standard rat comb, but I've - again - ignored the discard functions of Nezumi and Drainpipe Vermin and gone with the more combat-spicy Prowler and Typhoid rats. I've added 2x of both Slumlord and Ratcatcher, and that might be a bold move, but I just felt like i never really got any value of having just of each in the deck.
If you like it, do it, if you don't feel free to tell me why! :)