You only see it in Commander, or in recent Standard decks thanks to the Lorwyn Eclipsed reprint

3 Blind Seer Boris Devilboon Braids, Conjurer Adept Cabal Patriarch Cadric, Soul Kindler Celes, Rune Knight Circu, Dimir Lobotomist Cynette, Jelly Drover Damia, Sage of Stone Deekah, Fractal Theorist Derevi, Empyrial Tactician Donal, Herald of Wings Dralnu, Lich Lord Dynaheir, Invoker Adept Emet-Selch of the Third Seat Emet-Selch, Unsundered Emry, Lurker of the Loch Endrek Sahr, Master Breeder Ertai Resurrected Ertai, Wizard Adept Ertai, the Corrupted Eruth, Tormented Prophet Esper Terra Eutropia the Twice-Favored Fandaniel, Telophoroi Ascian Felisa, Fang of Silverquill G'raha Tia, Scion Reborn Gadwick, the Wizened Gale, Waterdeep Prodigy Gandalf of the Secret Fire Gandalf the Grey Gandalf the White Gandalf, Friend of the Shire Gandalf, Goblins' Bane Gandalf, Party Guest Gandalf, Shadow's Foe Gandalf, Spark Starter Gandalf, Wandering Wizard Gandalf, Westward Voyager Gandalf, White Rider Garth One-Eye Genku, Future Shaper Geralf, Visionary Stitcher Ghen, Arcanum Weaver Ghoulcaller Gisa Gisa and Geralf Gisa, Glorious Resurrector Glarb, Calamity's Augur Gogo, Master of Mimicry Gogo, Mysterious Mime Golbez, Crystal Collector

His companion, Jamie McCrimmon, is a stompy green creature who gets a buff to his power whenever you cast a Historic spell
You can have 52 poison counters, no cards left in your deck, and -100 life, and youre still in the game
This makes Goblin War Strike devastating in 1 vs 1 games, though in Commander multiplayer games, dealing all the damage to just one opponent isn't optimal
If both targets are illegal, the ability won't resolve at all