List of N3 implementations

cwm written in Python as part of the Semantic Web Application Platform
eye Euler Yet another proof Engine
eye-js JavaScript/WASM version of eye

In Progress

jen3 extending Jena system with full N3 support (william.van.woensel@gmail.com)
Ruby RDF::N3 a Reader and Writer for the RDF.rb ecosystem which includes limited provisional capabilities.

Incomplete

N3.js Lightning fast, asynchronous, streaming RDF for JavaScript
(note: does not support reasoning)
swish implementation in Haskell of N3 (also Turtle, formal semantics, graph isomorphism, etc)
(homepage mentions incompleteness)
AutoNomic backchaining reasoner with AE rules
(seems incomplete according to this?)
Linked Data-Fu implementation in Java of a subset of N3's features (RDF assertions, deductions) with special semantics regarding HTTP requests in rule heads
(reasoning aspect unclear - cannot access system)
RDFLib Python package for working with RDF. (note: does not support reasoning)
RoXi a Rust based streaming reasoner (command line + web version)

Archived

FuXi in Python using RDFLib see also gjhiggins's branch which works with current RDFLib.
Henry an SWI-Prolog