Links to some editors inspired by plan 9's acme.

Another Android/iOS app for viewing and editing org-mode files.
+ LaTeX rendering sounds interesting

MACSimizing TECO: A Note on the Invention of EMACS
by Adrienne Gaye Thompson [1] 2009-11-02
Found on https://dbpedia.org/page/Emacs, where the incorrect URL http://www.codeartnow.com/hacker-art-1/macsimizing-teco is used

GNU poke is a new interactive editor for binary data. Not limited to editing basic entities such as bits and bytes, it provides a full-fledged procedural, interactive programming language designed to describe data structures and to operate on them.
Home page: http://www.jemarch.net/poke

Found via a link on Ekaitz's blog https://ekaitz.elenq.tech/bootstrapGcc2.html

Emacs /ˈiːmæks/, originally named EMACS (an acronym for "Editor MACroS"), is a family of text editors that are characterized by their extensibility. The manual for the most widely used variant, GNU Emacs, describes it as "the extensible, customizable, self-documenting, real-time display editor". Development of the first Emacs began in the mid-1970s, and work on its direct descendant, GNU Emacs, continues actively; the latest version is 28.2, released in September 2022.

quiver is a modern, graphical editor for commutative and pasting diagrams, capable of rendering high-quality diagrams for screen viewing, and exporting to LaTeX via tikz-cd. See also the github page https://github.com/varkor/quiver

Poplog is a system (compilers, run-time, editor) for the languages Pop-11, Common Lisp, Prolog and ML.
Poplog was developed in the School of Cognitive and Computing Sciences at the University of Sussex and at ISL (now part of SPSS), and is distributed free of charge by courtesy of both organisations.

emacs-ng is based off of the master branch of emacs, and regularly merges in the latest changes(this branch includes the native compilation feature from Andrea Corallo).

This project should be considered an additive native layer over emacs, bringing features like Deno's Javascript and Async I/O environment, Mozilla's Webrender, and other features in development. emacs-ng's approach is to utilize multiple new development approaches and tools to bring Emacs to the next level. It is maintained by a team that loves Emacs and everything it stands for - being totally introspectable, with a fully customizable and free development environment. We want Emacs to be a editor 40+ years from now that has the flexibility and design to keep up with progressive technology.

SCAME is just another one of those ersatz EMACS editors.
The purpose has been to make it look as much as possible like
EMACS on TOPS-20 and AMIS on TOPS-10 and VAX/VMS. A lot of
things are still missing, and some new facilities have been
added to make it fit in better with the UNIX philosophy.

SCAME was first implemented in 1980 on a PDP-11/70 running UNIX
v7 at the University of Linkoeping, Sweden.
https://www.acronymfinder.com/Screen-Oriented-Anti-Misery-Editor-%28SCAME%29.html claims that the name stands for
Screen Oriented Anti Misery Editor

Mentioned on https://gunkies.org/wiki/Emacs_editors

It’s similar to vi as both are modal editors with curses interfaces. However, it differs from vi in that it has the same command syntax as ed. For example, in se to escape from append mode, you’d enter a line containing a single period instead of the vi way of hitting the escape key.

se has a long history dating back to the early 1980s. Beginning in 2013, Thomas Cort undertook the task of modernizing the early code and build system to get the software working on recent POSIX operating systems. The code base was straight forward and only used facilities available 25 years prior, and as a result, with a few modifications, it runs on many modern operating systems. Thomas' primary motivation is to preserve this bit of computing history. His goals are to squash any remaining bugs and make se as portable as possible. No major new features will be added.