Use case: 

I have created a new custom module called Makes to hold the names of thousands of different manufacturers.

I am trying to create a custom lookup field for Items that uses the custom module.

I am not able to select the custom module for the lookup field (the custom module is not listed).

Question:

How can I create a custom lookup field that references a custom module (like I can in Zoho CRM)?

If this can't be done, is there a workaround that is commonly used to achieve this?