The answer that I add here does not solve the implicit question of “how are there several root level folders in LINQPad ”. However, I think this gives a solution to the question of how to "include more than one [sic] folder in My queries to organize my codes?"
Technique 1 - Just add folders (perhaps worse than Technique 2)
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Powershell :
# By not changing the value for "Path," this will create a symbolic link in the current folder
# that is named whatever value is given for "Name," and it will be pointed to whatever value
# "Value" is set to.
new-item -ItemType SymbolicLink -Path . -Name "ExampleSharedScripts" -Value "Path to actual folder"
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