LINQPad 8 can only read code snippets from Visual Studio 2017
LINQPad also picks up any custom snippets that you've written for Visual Studio. These are stored in
<My Documents>\Visual Studio 2017\Code Snippets.
I tested. LINQPad 8 will not read User's code snippets from Visual Studio 2019 or Visual Studio 2022. I think these folder paths all should be considered as a default source of the code snippets in LINQPad.