I just realized you may have meant a larger variety of crops. If that's the case, continue to level up. As you may know each level up unlocks new fountains, products, and machines. Crops also are gained in level ups

Keep completing actions to gain experience. Collecting 1 crop = 1 experience point. Every activity has an associated experience value. Villagers will ask you for things and that is the fastest way to increase.

When you touch an existing crop, a scythe will show, run your finger along the crop(s) you want to harvest. There will be a dirt square. Touch that and your choices of plants will show. Select the crop you want to plant and then run your finger along the square(s) you'd like to grow your crop in

You dive. Dive and unlock things there and you will get different stone things which can be used to upgrade fountains.

As far as I can tell you can't find individual people here. But if you happen to come across them, just to the right of their user name there's a little bubble that says "follow". To find new people you can touch the game updates in the bottom right of your screen, if you order something from the trader panda you can touch the icon of the person he bought it from, and when you ask for help to increase the speed of a job, you can touch on the helpers name.

Use the rare plant in the bee hive

I was stuck there as well and you may not have to get to 38, but you will have to continue to level up. It's an unfortunate plateau in the game

Keep trading and fulfilling villager requests. Additionally, make sure all of your building improvements are done. All of these things will level you up.

Use your alchemists bench to convert it experience points to level up