In order to upgrade your tools or expand your safe, you need artifacts. These particularly valuable items are made up of individual parts that, when put together, form a collection that is crowned by the legendary artifact.
You can upgrade your tool in the laboratory. You will receive the safe after successfully completing all tutorial missions.
There are different collections, artifacts and items in Cats Empire. Here you get an overview:
consists of: tape, screw, pliers, saw, tool
consists of: beet, brush, carrot, bottle, pestle
consists of: respirator, saucepan, garlic, gloves, soap
consists of: button, thimble, ball of yarn, yarn, bow tie
You can get the individual items for creating a collection and thus an artifact from the lucky mail, from killed cats and as a reward.