A fairly common practice is to detail multiple components (generally parts, but also possibly assemblies) on a single sheet, and have a Bill of Materials for all items on that sheet up in the corner of the sheet. As common and practical as this sounds, Inventor does not facilitate it in any way.
There is no way to place a Parts List on a sheet that lists all the components on that Sheet. Parts Lists have to be linked to an Assembly, but there may not be an assembly that corresponds exactly to the items detailed on a particular sheet.
So our only options are to either manually type up a Parts List table (very bad idea), or create a dummy assembly that contains the items detailed on the sheet and use that to create the sheet's Parts List. This works, but it requires creating and keeping up with an extra assembly file for every single sheet, and also requires manually keeping the components in the assembly in sync with the items detailed on the sheet.
I propose that there should be an option to link a Parts List to the sheet itself, and then treat the sheet essentially like an Assembly, where each View on the sheet represents a component "in" the sheet. A Parts List can then be placed on the sheet in the "Structured" or "Parts Only" format, listing either each component which has a View on the sheet (if Structured is chosen) or all parts which appear in a View on the sheet (if Parts Only is chosen).