Knowing what cards other players have in their decks can give you early indications of their strategies
Sword of Once and Future Sword of Once and Future still does a lot despite being the worst Mirran sword
The deck that did this most famously was Prosperous Bloom, refilling its mana and thinning its deck by combining Squandered Resources with Natural Balance or simply to boost its way to its first Cadaverous Bloom or Prosperity
In Commander, there has to be an activated abilities deck that works with the graveyard
Released by Wizards of the Coast alongside other supplemental sets, this set includes 24 Jumpstart Boosters featuring 46 possible themes, such as Goblins and Ninjas
In the right go-wide deck, such as Elves or Goblins, you can easily get boosts in the +4/+4 to +5+5 range going, too, which are very hard to deal with