Hi Yokoharu. Welcome to ATP, I hope you find a swap or decide to organize one yourself. Dave wrote some nice software to make seed swaps easier, but someone still has to volunteer to be the central person.
http://garden.org/apps/swap//
(Or look at the blue menu bar on the far left. The 8th entry is "Seed Swaps". However, none are active right now for vegetables.
I would probably join a swap that includes vegetable seeds. I have some old tomato and pepper seeds, but I stopped collecting them when I realized that I would need plastic tunnels to reliably ripen most varieties.
