iNaturalist has worldwide observations of biological organisms. You can do a bulk download here. This data is not strictly "open", because login is required. However it is free to register.
Use this query to download observations of Suborder Anisoptera (Dragonflies): quality_grade=any&identifications=any&taxon_id=47927
There are currently 357100 ...
Railroads and the Making of Modern America has links to the following downloadable historical US railroad data. I didn't investigate the actual geospatial extent of these railroad datasets, so I can't promise they have Colorado railroads. Here's a wayback machine link in case the original site goes down.
Historical GIS: Depots of the ...
You can Find the information city wise here:
This is free data and can be downloaded in bulk as well.
One of the sample of zoning is as provided here
If you have a budget as well then you can get the complete data on arcgis.
Sample of the same in action can be viewed here
Bonus: You can have other detailed ...
Inland bathymetry data for South Africa is not easy to locate. I found some sources that seem promising. I don't have time right now to fully dig through each of these sources to see if they have exactly the right thing, so here's a link dump of all the relevant-sounding data sources I found. If you do find exactly what you want at one of these links, please ...