I'd love to see what kind of variations this brings.

Are carrots, netherwart and mushrooms excluded from this plugin?

We have this, bold being a sellable plant:

Snowy:                      None
Cold:                         Beetroot, Sweet berry bush
Temperate:              Melon, Potato, Pumpkin, Sugarcane, Wheat
Lush:                         Cocoa, Bamboo
Dry:                           Cactus
Ocean:                      Kelp
Nether:                     None
End:                          Chorus Flower

So of the 5 sellable plants included here, 1 grows best in the cold biome, and 4 in the temperate biome. It might not be wholly realistic, but I think putting some more plants in the lush or dry biomes would help the variation. (Everyone might just settle in plains and forests otherwise.)

Oops, left carrot out of the post. It is included though, I edited the post to add carrots. They're Cold biome.
Netherwart can only be grown in the Nether, unless you have a nether rank. So its still a nether plant and you can sell that. Growth rates were unchanged. So you can include that as a sellable item for your table.
Mushrooms I left alone.
Looks like it should be chorus fruit instead of flowers. Which means the plant itself has to grow slower. So we can change that and now end in your table has a sellable item as well.

Sweet berries prices are already being talked about so we can add them to the shops. Maybe we should also have that discussion for cocoa? Melon should probably be moved to Lush. That way it would be 3 cold, 3 temperate, 2 lush, 1 Nether, 1 End. I don't think that would stop people from settling in snowy biomes or dry biomes, since there is a plant that's only 1 group away so it'd be 80% rate.

Also not sure it would even be noticeably slower if you say, grew carrots in a snowy biome. Lets put some hard numbers on it. Depending on how you plant your fields the growth time is roughly 30-60 minutes. If it grew 20% slower you're looking at an increase of 6-12 minutes. If you plant your crops and walk away to go do something else I'm not sure if you would even notice it took an average of 9 minutes longer. 20% isn't a lot of time when we're talking small time frames.

Adjusted with the above your table would then look like this

Snowy:                      None
Cold:                         Beetroot, Carrot, Sweet berry bush
Temperate:              Potato, Pumpkin, Wheat, Sugarcane
Lush:                         Melon, Cocoa, Bamboo
Dry:                           Cactus
Ocean:                      Kelp
Nether:                     Netherwart
End:                          Chorus Fruit

I think Snowy and Dry biomes would be ok with not having a sellable plant native. For snowy you could do carrots or berry bushes, and for dry you could do melons.

Gonna be nice to see players start doing different things depending on their biomes, instead of it being potatoes and wheat.

I agree! Variety would be nice. If we want to encourage usage of all the different crops, then all crops should be sellable in the markets. For example, ocean biome can only grow kelp at 100%, yet it cannot be bought in server shops. There is no crop useable in the ocean (for selling directly and at 100%). And all other crops grow at 10%. There really should be some kind of sellable crop in all biomes (for sure, crops that grow at 100% in a biome). There is only so much ore under you. So if one only relies on ores, they will to have to keep moving farther and farther away from home (if you live on the ocean). And fishing...that is not for everyone...standing and right clicking for long periods of time...please, no. Not as the main cash item. Even if they live on/in the ocean.