Updated to Game Version 2.12.3, Asset Version 142 (January 21st, 2020).
Crafting Stations are spread throughout Pocket Mortys and allow you to combine two or three items together into new items. Several crafting stations can be found in the Citadel of Ricks, and more are found randomly throughout the various dimensions.
There is a limit to how many of each item you can carry, so it is a good idea to combine base items when you can. There are are currently 34 campaign recipes and 18 multiplayer recipes in the game (see the table below). Use the filters to toggle between multiplayer and campaign recipes, and to show/hide icons, names, or descriptions.