You could generate such a dataset using Python. A simple approach would be to generate a set of (x, y) coordinates, partition the set, then assign a distinct value for the z coordinate for each partition. An example with 100 points divided into 5 linearly separable partitions:
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt
The World Health Organization maintains a list of International Nonproproprietary Names (INNs) for drugs in Latin, English, French and Spanish. You can download this list at https://www.who.int/medicines/publications/druginformation/innlists/RL82_pre.pdf
This Scrabble dictionary shows you the validity of a word in real-time as you plug it in. I also like this site b/c they have 2 million words (and counting) in their database and let you vote and collaborate on their resources. Cheers :)
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If you visit https://sdmdataaccess.sc.egov.usda.gov/QueryHelp.aspx and download the "Table Column Descriptions Report (741K)" PDF, you will get a list of all tables (and column names) for your data.
You can then go to https://sdmdataaccess.sc.egov.usda.gov/Query.aspx and make queries like SELECT * FROM chaashto. You will have to ...
The easiest way to make your dataset eligible to be included in Dataset Search results is to upload it to a repository that adheres to metadata standards used by Dataset Search. There are many such repositories. You can try the following: