Hapatra, Vizier of Poisons is the classic commander for this archetype, and, as well as Massacre Girl, new cards include the Jurassic World dino Spitting Dilophosaurus
Synergy, Griefing, Staples, Building a Doran Deck ) My current Commander decks (and links to decklists) : Ruhan of the Fomori (lots of equipment and infinite attack steps) Phage the Untouchable (actually casting Phage from Command Zone!) Ghave, Guru of Spores (Melira Combo) Glissa, the Traitor (undying artifacts!) Previous Commander decks currently on hiatus : Grimgrin, Corpse-Born (Necrotic Ooze Combo) Damia, Sage of Stone (Ice Cauldron shenanigans) Geist of Saint Traft (Voltron-ish) Glissa Sunseeker (death to artifacts!) Jor Kadeen, the Prevailer (replacing Brion Stoutarm in Mo Myrs) Thelon of Havenwood (Campfire Spores) Melira, Sylvok Outcast (combo killa) Konda, Lord of Eiganjo (The Indestructibles) Vorosh, the Hunter (proliferaTION) Progenitus (Fist of Suns and Bringers) Savra, Queen of the Golgari (Demons) Uril, the Miststalker (my "more competitive" deck)
A relatively unknown Magic: The Gathering card just saw an enormous price spike, thanks to a recent MTG ban
By playing enough of both, you'll be passively gaining lore, draining your opponent, and have a board state that will be very tricky for your opponent to unpick in time
It commonly goes with commanders like Krark, the Thumbless or Vial Smasher the Fierce that have strong triggered abilities to double, but most decks are happy to have access to blue
