Beasts of Bogardan is a Beast
Start Your Engines on a 6 mana Commander is asking a lot , but given you get cost reduction based on your speed and not having Max Speed (and the same goes for your buff to the team), the payoff seems reasonable

Aang's Journey Aesi, Tyrant of Gyre Strait Analyze the Pollen Ancient Greenwarden Azusa's Many Journeys Badgermole Cub Beanstalk Wurm Beanstalk Wurm Benalish Emissary Bioengineered Future Blighted Burgeoning Brutal Suppression Bumi, Unleashed Buried in the Garden Case of the Locked Hothouse Chocobo Camp Crop Rotation Crypt Ghast Dance of the Tumbleweeds Dawn's Reflection Deprive Devour in Flames Double Play Druid Class Dryad of the Ilysian Grove Elvish Guidance Enter the Unknown Escape to the Wilds Exploration Exploration Broodship Explore Fastbond Fertile Ground Flubs, the Fool Fumarole Gaea's Balance Gaea's Touch Gauntlet of Might Gauntlet of Power Ghirapur Orrery Glittering Frost Goblin Ruinblaster Grab the Prize Grow from the Ashes Harrow Hearthhull, the Worldseed High Tide Hugs, Grisly Guardian Icetill Explorer Iridescent Vinelasher Joint Exploration Journey of Discovery Kellan, Inquisitive Prodigy Kellan, Inquisitive Prodigy Kiora, the Crashing Wave Littjara Mirrorlake Loot, Exuberant Explorer Lord Windgrace Magma Rift Magmatic Insight Mana Flare Market Festival Merciless Resolve Mina and Denn, Wildborn Mind Games Moraug, Fury of Akoum My Tendrils Run Deep Nahiri's Lithoforming Naya Nightscape Battlemage Nirkana Revenant Nissa, Who Shakes the World

Collectors were willing to pay hundreds of dollars for a single one of these cards back then, and even today you could be sitting on anywhere from $200 to $2,650 for a Shining Gyarados depending on its condition
But it can also go in a deck which wants to play creatures onto the board on turns 1-3, and then use this creature to do the last bit of draining reach, putting a flier out there that threatens more reach if your opponent kills it