Blocker (pm_blocker) — Allows log processing to be paused and resumed

Buffer (pm_buffer) — Implements disk- and memory-based buffering for log data

Event Correlator (pm_evcorr) — Provides conditional execution based on correlation between events

HMAC Message Integrity (pm_hmac) — Adds a checksum to each event for later verification

HMAC Message Integrity Checker (pm_hmac_check) — Validates event checksums generated by pm_hmac

De-Duplicator (pm_norepeat) — Discards duplicate events and adds "last message repeated n times"

Null (pm_null) — Provides a dummy processor for testing, custom processing, or scheduled execution

Pattern Matcher (pm_pattern) — Performs efficient pattern matching with an XML pattern database file