Dungeon Map enters the battlefield untapped, also taps for mana, and activates for three mana (and thankfully, no tapped legendary creatures)
Probably best suited as lieutenant or a captain or something
Many commanders like The Gitrog Monster give you tips about what they want, usually by calling out specific card types, zone, or game actionsother similarly simple commanders include Isshin, Two Heavens as One, who demands attack triggers, and Atraxa, Praetors' Voice, which needs some sort of counter to proliferate
It gets even better when combined with the typical ETB/LTB effects Mardu has access to, as well
Breaking Point
Equip Legendary Artifact - Equipment Color tag templates(None) Jousting Lance Equipped creature gets +2/+0