These massive, iconic fliers are sure to dominate any game, especially the Commander format, which welcomes huge creatures like them to close out games
Ajani's Aid tutors for the Ajani from its Planeswalker Deck, and you can sacrifice it to throw pocket sand into a creatures eyes for some damage prevention
It also sees competitive play in Modern, and sometimes shows up in Legacy
Mishras Factory, unlike Strip Mine, wasnt a staple for one particular type of deck, it was just inserted into almost every type of deck, depending on the builder/player
It can just end the game on the spot
So, if you're ready to unleash the Ur-Dragon's fury and leave a trail of scorched lands in your wake, the Dragon's Roar Commander Deck is your golden ticket