Mushrooms are everywhere. There used to be a subreddit of "weird mushrooms" like growing out of people's couches or in the bathroom, etc. In all cases, this is a sign of rot due to water intrusion.

You can grow mushrooms at home, it is fun. The only risk is that the mushrooms with high spore production are not great to have in a closed residence, especially oyster mushrooms which produce very high spore loads. There are vendors who produce cultures of sporeless oyster which can be used to grow oyster mushrooms indoors.

Outdoors, at least in most temperate areas, you are limited to things like shitake on logs or winecaps. The latter are incredibly easy to grow, and very good taste wise, but they are temperamental and basically grow on their own schedule, infrequently.

For the curious: https://www.reddit.com/r/mushroomID/