X/2 creatures can also be affected if you have Golgari Thug or Narcomoeba
But let us get serious: what are you going to do with churning out 1/1 creatures
You can pay one black mana and sacrifice another creature to have a player mill three cards, which is cool, but you can also pay one life to add one colorless mana which can only be used to cast spells from your graveyard
Still worth inspecting centering and edges before storing
Although there are many ways to put -1/-1 counters on creatures, Im considering only MTG cards that put -1/-1 counters on creatures (or on themselves) via their own card text
Number 25 Language English Not Legal Formats Alchemy, Brawl, Commander, Competitive Brawl, Historic, Legacy, Modern, Pauper, Pioneer, Standard, Timeless, Vintage