Here are the data structures with brief descriptions:

pa_buffer_attr	Playback and record buffer metrics
pa_card_info	Stores information about cards
pa_card_profile_info	Stores information about a specific profile of a card
pa_channel_map	A channel map which can be used to attach labels to specific channels of a stream
pa_client_info	Stores information about clients
pa_cvolume	A structure encapsulating a per-channel volume
pa_ext_stream_restore_info	Stores information about one entry in the stream database that is maintained by module-stream-restore
pa_mainloop_api	An abstract mainloop API vtable
pa_module_info	Stores information about modules
pa_sample_info	Stores information about sample cache entries
pa_sample_spec	A sample format and attribute specification
pa_server_info	Server information
pa_simple	An opaque simple connection object
pa_sink_info	Stores information about sinks
pa_sink_input_info	Stores information about sink inputs
pa_sink_port_info	Stores information about a specific port of a sink
pa_source_info	Stores information about sources
pa_source_output_info	Stores information about source outputs
pa_source_port_info	Stores information about a specific port of a source
pa_spawn_api	A structure for the spawn api
pa_stat_info	Memory block statistics
pa_timing_info	A structure for all kinds of timing information of a stream