As James said above - NAPA, O'reilly's, and CarQuest all sell Wix. NAPA and CarQuest brand them as their own, but they're still Wix filters.
There are only really a few brands out there aside from OEM and most all of them are made by Fram/Honeywell, Purolator, and Wix. Wix has the majority out there though and they're the best filters on the market for the money. Purolator is also another excellent filter as well though, which is sold mainly by Advance Auto Parts, and you can occasionally catch them on sale too.
I despise anything Fram and thankfully Microguard is their only off-brand that i'm aware of. They make horrible, horrible filters and it's not worth saving a very small amount to give them a shot.
There's honestly no need for a cross reference or any research for air, or oil filters if you're buying a standard one from a retail store. Almost all of them are made the same way, because they're made by a specific manufacturer and packaged under a different name, and they preform identically. Now, if you're looking for a performance filter and are trying to decide between something like a K&N, Amsoil, AEM, and ect then research is worth while, but for a standard store bought filter you're wasting your time. I worked in retail auto parts for 7 years - there is nothing worth researching aside from what has already been mentioned.
<waits for the Fram lovers to show up and defend it's honor>
