what are all the different possible ways 'Requestors can search an item' from a Blanket Purchase Agr

Hi,

We are trying to make our Catalogs as much intuitive as possible.

What are the different ways, the users can find items/services.

I am looking for all the possible ways to train the requestors on the same.

Eg. 1) Search with BPA number

      2) Search with BPA description

      3) Search with supplier name

      4) Please give other ways