Not all rats lean into this strategy, however
Enter Stitch, Rock Star a six-cost super rare that flew under the radar for months
Permanents with cumulative upkeep gain an age counter on your upkeep, then prompt you to pay the cost for each age counter on them
Alternatives Pack Rat is the only card I can think that functions similarly to Cryptbreaker, which is an enabler and reward card that makes tokens and functions as a discard outlet
If you're interested in how these will play in Limited formats, check our Modern Horizons 3 Limited Set Review where we rate all the cards, and our MH3 Sealed Guide if you're specifically interested in Sealed or our MH3 Draft guide for, well, Draft
I was all set to buy another copy until I saw that the card is more than 15 bucks right now