See the Full PowerShell Command History (PSReadLine)
Get-History only shows the current session. PSReadLine saves every command in a text file:
%APPDATA%\Microsoft\Windows\PowerShell\PSReadLine\ConsoleHost_history.txt
Open it or search it directly:
notepad (Get-PSReadLineOption).HistorySavePath
Get-Content (Get-PSReadLineOption).HistorySavePath | Select-String "docker"
Tip: press Ctrl + R in the console for reverse search.
Careful: anything typed on the command line, including passwords, can end up in this file.
More info.