Similar to how mono-black decks have used the optional looting (draw-then-discard) from Learn cards, Blood tokens can help to justify deck building with more situational cards
Best Green Card: Delighted Halfling Yes, I know
Gallery and List of Poison Cards In addition to cards that have infect or toxic, these are cards that can put poison counters on a player: Crypt Cobra Sabertooth Cobra Suq'Ata Assassin Pit Scorpion Marsh Viper Swamp Mosquito Serpent Generator Hand of the Praetors Ichor Rats Relic Putrescence Virulent Wound Pistus Strike Decimator Web Caress of Phyrexia Reaper of Sheoldred Fynn, the Fangbearer Ajani, Sleeper Agent Norn's Decree Phyresis Outbreak Prologue to Phyresis Infectious Inquiry Vraska, Betrayal's Sting Vraska's Fall Infectious Bite Etali, Primal Conqueror Etali, Primal Sickness Persuasive Interrogators Bloodroot Apothecary Virulent Silencer There are other cards like Corrupted Resolve and Mycosynth Fiend that mention poison counters but don't actually distribute them
There are a couple of upgrades you can pop on Limit Break to quickly transform it from a pretty good deck to a pretty great deck
Five mana for a rock that produces WUBRG is pretty cheap, and youd end up paying more for it to enter untapped (though how much more, when Chromatic Orrery is seven mana, Im not sure)