The IFC sample files are hosted on GitHub.
The BIM Whale contains 6 different sample files.
Notice that left clicking will open only the file in a new tab.
The Simple wall sample file can be downloaded from here:
The Many simple walls sample file can be downloaded from here:
The Tall building sample file can be downloaded from here:
The Large building sample file can be downloaded from here:
The Basic House sample file can be downloaded from here:
The Advanced project sample file can be downloaded from here: