Expanding all columns simultaneously in Power Query

Question

Need help expanding all columns in a spreadsheet simultaneously using Power Query. I have transposed the spreadsheet from this:

to this:

Each table is a long column of values (9,000+ rows). I would like each column to be a separate ID. Expanding columns manually would be a tedious job and our team is adding data from new study participants (IDs) regularly, so I need help creating a code that can expand all columns simultaneously without having to indicate the column names (IDs) in the code. Thank you for your help!

This is the code I'm currently using:

let
Source = Folder.Files("folder address goes here"),
#"Filtered Rows" = Table.SelectRows(Source, each ([Extension] = ".xlsx")),
#"Removed Columns" = Table.RemoveColumns(#"Filtered Rows",{"Content", "Extension", "Date accessed", "Date modified", "Date created", "Attributes"}),
#"Added Custom" = Table.AddColumn(#"Removed Columns", "filepath", each [Folder Path]&[Name]),
#"Removed Columns1" = Table.RemoveColumns(#"Added Custom",{"Folder Path"}),
#"Added Custom1" = Table.AddColumn(#"Removed Columns1", "Custom", each Excel.Workbook(File.Contents([filepath]))),
#"Expanded Custom" = Table.ExpandTableColumn(#"Added Custom1", "Custom", {"Name"}, {"Name.1"}),
#"Filtered Rows1" = Table.SelectRows(#"Expanded Custom", each ([Name.1] = "Heart Period Time Series")),
#"Added Custom2" = Table.AddColumn(#"Filtered Rows1", "Custom", each fnImportExcel3([filepath],[Name.1])),
#"Removed Columns2" = Table.RemoveColumns(#"Added Custom2",{"filepath", "Name.1"}),
#"Replaced Value" = Table.ReplaceValue(#"Removed Columns2",".xlsx","",Replacer.ReplaceText,{"Name"}),
#"Transposed Table" = Table.Transpose(#"Replaced Value"),
#"Promoted Headers" = Table.PromoteHeaders(#"Transposed Table")

Answer 1

You may use following technique:

let
    t1 = #table({"1"},List.Zip({{"a".."f"}})),
    t2 = #table({"2"},List.Zip({{"d".."g"}})),
    t3 = #table({"3"},List.Zip({{"a".."e"}})),
    input = #table({"Name","Custom"},{{"B1",t1},{"B2",t2},{"B3",t3}}),
    toList = Table.TransformColumns(input, {"Custom", Table.ToList}),
    output = #table(toList[Name],List.Zip(toList[Custom]))
in
    output