The BPMN spec contains way over 100 different object types that can be used in the different model types. There are special rules about how to use them, which I will explain in later lessons. This article contains an overview of the available objects.
BPMN Objects Overview
Depending on your use case and point of view, the amount of available object in the different BPMN models might be a blessing or a course. Most likely business people will shy away from the notation and might see it as “too complex”, while technical folks who want to implement a workflow system might welcome the possibilities to express even complex situations in a (relatively) simple way.
However, there is a thin line – due to the openness of the specification in the object definition, as well as the modeling style that allows to express the same thing in multiple ways – for Enterprise Architects who want to standardize on BPMN for the process layer to walk on, since some mappings are not possible or can be only achieved with workarounds.
(BPMN 2.0 poster created by the BPM Initiative Berlin; downloadable at http://bpmb.de/poster)