Are those ornamental, like gourds or edible pumpkin?
I have seen them sold in stores as fall decorations.
This fall I may buy some and get the seeds.

I have lots of gourds about the sime size but pear-shaped.
When they mature have about 250 seeds and no flesh. And get very hard shell like lagenaria gourds.

The Jack Be Little are open-pollinated, edible, mini pumpkins. Seeds are readily available in the beginning of the season. I think they cost about $1.19 a pack at Lowe's. They are growing straight up a trellis quite easily as well. The vines are about 8 feet long, but they are showing signs of powdery mildew. It's been very rainy and humid here. Plus I have them in a spot that gets a good bit of shade. They would probably be more happy in a sunnier spot, but they are still doing well. My only advice would be to plant at least two vines. I've had some female blossoms come and go when the vine didn't have any male blossoms open at the same time. It sure is a cute, tiny pumpkin.

Here is a link that might be useful: Kim's Garden