Reference

Appenders
AppenderAWSCloudWatchLog	Log to AWS CloudWatch Logs
AppenderDbi	Log to databases via DBI
AppenderDynatrace	Log to Dynatrace via HTTP
AppenderDt	Log to an in-memory data.table
AppenderElasticSearch	Log to ElasticSearch
AppenderGmail	Send emails via the Gmail REST API
AppenderSendmail	Send emails via sendmailR
AppenderPool	Log to databases via pool
AppenderPushbullet	Send push-notifications via RPushbullet
AppenderSyslog	Log to the POSIX system log
Other functions and classes
LayoutDbi LayoutSqlite LayoutRjdbc LayoutRjdbcDb2 LayoutDb2 LayoutMySql LayoutPostgres	Format log events for output to databases
LayoutElasticSearch	Format log events for output to ElasticSearch
LayoutDynatrace	Format log events for output to Dynatrace
Serializer SerializerJson	Serializers
select_dbi_layout()	Automatically select appropriate layout for logging to a database
unpack_json_cols()	Unserialize data frame columns that contain JSON
transform_event_dynatrace()	Transform a log event for Dynatrace
Abstract classes For developers only
AppenderDigest	Abstract class for digests (multi-log message notifications)
AppenderMail	Abstract class for email Appenders