It looks like some sort of winter squash.

"There are 2 different kinds of leaves"

Every plant seedling has two different kinds of leaves. The first two (or one, or more as in the case of conifers and some other plants) leaves are called seed or embryonic leaves, or cotyledons. After that the plant starts developing true leaves that are characteristic for the plant.

Yep, winter squash. I do direct composting, and they come up all over the yard every year, but none ever grow into anything. However, when I had an actual compost pile, I had them come up right out of the pile, along with cantaloupes and watermelons sometimes. I got some nice fruit/veggies off of those volunteer vines.

Yup squash. They sprout so easily in our compost pile. In fact the rule here is no seed head of any kind go in the compost pile.

Hubs must have tossed a somewhat unedible tomato last fall because there is about a dozen very healthy tomato plants growing there!