while Relentless Rats just cares about other cards specifically called Relentless Rats, Rat Colony just cares about Rat cards period, opening up the possibility of playing other good Rat cards in the deck
There are a handful of creatures with useful enter the battlefield triggers, and worst case scenario, the blink will cause your lifegain effects to trigger so Hope can mill even more cards
All those Unicorn tokens can tap out to let the Meteor Golem flicker one more time to get rid of the last blocker or destroy an opponent's Propaganda
A quick word of warning to the uninitiated: this isn't your standard MTG set
Do I allow the 2/2 that is attacking me through to take two damage, or do I block and kill it but give you a card
Some of the reprints are nothing special due to low value or power, but other reprints are seeing their first reprint since their original printing and are great for many decks while being easily accessible