Turn-based combat, monsters, enemies, a whole story unfolding
A two-mana 1/1 flyer isnt too impressive, but on each of your end steps it makes your Dragons in hand one mana less to cast
First, Commander precons are typically much lighter on wraths and sweepers than other Commander decks (this is true again with Commander 2020 , where some decks have a wrath or maybe two but far less than the 6+ sweepers you often see in a non-precon Commander deck), which is a big boost in power for a deck like Mardu Humans that is looking to go wide with small creatures
Not paying mana for the extra cards is great, even if it will only trigger once per turn
The most infamous involved Heliod, Sun-Crowned - a two card combo that lets you end the game
Yoni Skolnik, a principal game designer at Wizards of the Coast, wrote in a June blog post that green-white best aligned with the identity of a summoner, which explains why both Yuna and Garnet from Final Fantasy 9 share that color spread