I never knew that about seeds vs. sets. I always wondered why my onions did not store well, despite good conditions. Once i get this Allium Leaf Miner problem under control and start really growing onions again, I'm def going to try seeds.
Re: Leaf bags. I got a hoof pick once. And yes, several small toys. Best was 4 uprooted geraniums...all of which sprouted and grew once they were replanted and brought indoors. Worst was an entire colony of moles! For a couple of years the lawn was a mess, then the cats stepped in and took control of the situation.

I'd have also been very happy to get those geraniums! Not the moles though. Hopefully no critters were imported with my leaves. I hadn't thought about anything like that being in a bag, however one year when we were dumping, spreading and rototilling leaves into the soil I did find 2 black widow spiders on the outside of one of the bags before we moved it.