Fertile and productive.
Usually applied to land, as in “a lush, fecund island.” Or to the land of a lucky farmer, tilling his “fecund plots that keep his neighbors in envy.”
However, fecund means fertile and land isn’t the first bearer of fertility that usually comes to mind.
“For all the pro-choicers out there who still complain that the fecund high schoolers of 16 and Pregnant and Teen Mom glamorize teen pregnancy–you should stop complaining.” —The Atlantic
Beyond babies and vegetation, something that’s fecund can also produce a lot of new ideas.
“If Dick hadn’t such a fecund imagination, he never would’ve finished so many novels and short stories.”