Generic lands like Adventurer's Inn and Capital City dont have any colored mana symbols in their rules text, so they have a colorless color identity, and you can play them in any Commander deck
If Dredge is forced to deal with those, it cannot develop properly
In this format, you'll build a Commander-style deck around a legendary creature or Planeswalker and play 1v1 games on MTG Arena
The last advantage is that Rat Colonys power boost counts all other rats in play, including Verminister and its tokens, Marrow-Gnawers brood, and so on
Each dragon has unique abilities and strengths, ranging from massive damage-dealers like Drakuseth, Maw of Flames to card-drawing engines like Dragonlord Ojutai
JPN boxes at ~$30 make the box route especially attractive