If you don't want to hunt through all the HAVE lists, you could ask on the Chat thread.
Link to the current "chat" thread:
http://cubits.org/ellasgarden/...
Ella will ask you to offer at least a few kinds of seeds yourself, before actively requesting specific seeds by "oinking". If you hear about something great on the chat thread, you can just copy-paste a list of seeds that you're willing to give away into what they call the "Piggy Database", and you're an Instant Piggy in good standing.
