Mushrooms?

Verdant and Charming mushrooms are available in all seasons.
Spicy Mushrooms are available in Summer and Winter
Lovely Mushrooms are available in Fall and spring.
Nightly Mushrooms in Winter.

They are all available in the same spawn points in the Bramblewood neighborhood. There are four spawn locations that I'm aware of and can remember (My sims lived there for a while):

In the the large ruins up the hill just across from the creature keeper's house (literally inside the ruins, enclosed by the crumbling walls).

Just down from the ruins headed toward the bridge over to the park.

About halfway between the park and the waterfall alongside the creek (on the waterfall side of the creek}

By the bench that's along the path up the hill to the cottage by the waterfall.

If you don't stay in the neighborhood long enough for them to sprout, you won't find them. If you live there on the other hand, they sprout like crazy, especially if you have the green eco-neighborhood boost, because at those spawn points new mushroom plants keep spawning, so after a few days you get to harvest like 5+ at each spot.

If your sims don't live in the Bramblewood neighborhood, just get a tent and spend a few days at the national park there. You'll be filled with mushrooms before you leave. Just make sure to go during whichever season matches which mushroom types you need.

I struggled to find these so I downloaded them from the gallery. So they are seasonal though that makes sense now.

If you find the badgers, they will lead you to the mushrooms.
However! Beware of the snake! :o

https://www.youtube.com/watch?v=EIyixC9NsLI