This page contains several circuits for operation on LTspice, they are not quite as simple as the "Simple circuits" section.
As always simulation will not show all aspects of the performance of the real circuit. There will be circuit parasitics which are not included in these simulations.
The categories covered include, some really simple circuits, simpler filters, the common emmitter amplifier, and op amps and comparators.
in case of any difficulties downloading, the following is this section as a zip file.