You know, I've wondered myself about this for many, many different figures. The old format of the TIG guide listed a few such associations, but I am guessing the info was scrapped because it was so limited (and not definitive...just because blaster X was verified for figure Y on card Z, that doesn't mean there weren't other legit combos of different weapons and figures on certain cardbacks).
I also noted that some references, such as the 'rough texture' Jawa blaster being included with Meccano Jawas has led to inflated eBay prices for rough texture Imperial Blasters now also proclaimed to be "Meccano Exclusive," although I am not aware of any evidence of this MOC or otherwise (I could be wrong, but I've got an awful lot of those in Kenner collections bought domestically). That was a horrid run-on sentence but the point is I can understand the concept of not including definitive information in a database that has effectively become the definitive source of reference for vintage SW accessories.
I don't have any MOC myself, and it is a pretty big thing to ask collectors with large MOC collections to detail photo the weapons included in each MOC, and you'd need a LOT of that to begin to approach definitive!
Although I suppose if enough people signed on it might be doable, in time.