log4stash is a log4net appender for easy logging of exceptions and messages to Elasticsearch indices.
You can configure few filters to analyze log events before they got sended to Elasticsearch similar to the filters on logstash.
The udp-forwarder is an open source library for Web APIs. It grabs http requests sent to the API, creates a rich log event in a JSON format and sends it to a remote log service, like Logstash, via UDP.
Serilog http sink for logstash. Also there is a ECS enricher that converts all properties of LogEvent to elasticseach ecs schema before send to logstash. For more information please reffer to GitHub Repository.