This page shows "Type F" Last Move problems.
The game is to find diagrams such that the stipulation "Colour the units. Last move?" has a unique solution. Checks are allowed in Type F - indeed in most cases it would be very hard to find a solution which does not require a check.
Positions exist for all 60 Type F tasks, but in most cases we don't know if those found are minimal.
A couple of examples have a slightly smaller number of pieces, but at the cost of specifying that Black has the move. This brings the total number of positions up to 62.