Transmuting a commander into a creature with an irrelevant body and no abilities shuts down lots of decks reliant on their commander to function and forces them to find a way to get it back in the command zone before replaying it

Akoum Alchemist's Refuge Aluren Arlinn, the Pack's Hope Azula, Cunning Usurper Blur of Heroism Borne Upon a Wind Breath of the Sleepless Captain Mar-Vell, Space-Born Cherished Hatchling Complete the Circuit Emergence Zone Final-Word Phantom Gandalf the White Gandalf, Friend of the Shire Heliod, the Warped Eclipse High Fae Trickster Hypersonic Dragon Kianne, Corrupted Memory Leyline of Anticipation Liberator, Urza's Battlethopter Mai and Zuko Najal, the Storm Runner Prophet of Kruphix Quick Sliver Quicksilver, Speedster Raff Capashen, Ship's Mage Rattlechains Renari, Merchant of Marvels Rootwater Shaman Sally Sparrow Shimmer Myr Sigarda's Aid Singer of Swift Rivers Skittering Cicada Tawnos Teferi, Time Raveler Tidal Barracuda Valley Floodcaller Vedalken Orrery Vernal Equinox Vivien, Champion of the Wilds Whirlwing Stormbrood Whirlwing Stormbrood Winding Canyons Wizards of Thay Yeva, Nature's Herald
Consider whether your skills lean toward Limited or Constructed events
If a card had a low of $2, a mid of $5, and a high of $7 in Scrye, you were less likely to trust that $5 number because you knew that it varied pretty widely
Historic is the Modern and Legacy analog for Magic: The Gathering Arena
If you really dont want your opponent to have Urza's Tower, or Nykthos, Shrine to Nyx, or Phyrexian Tower, heres a way to get them gone for good