Record some official and unofficial higan resources.

README.md

@@ -48,14 +48,51 @@ see "Unofficial higan resources" below.
 Official higan resources
 ------------------------
 
+  - [Official homepage](https://byuu.org/emulation/higan/)
+  - [Official forum](https://board.byuu.org/viewforum.php?f=4)
+
 Unofficial higan resources
 --------------------------
 
-- the git repo
-- hunterk's quark shaders
-- mercurial magic for MSU-1 games
+  - [Source code repository](https://gitlab.com/higan/higan/):
+    archives official higan releases
+    and WIP snapshots
+    since approximately v067r21.
+  - [Quark shader repository](https://github.com/hizzlekizzle/quark-shaders)
+    collects shaders that higan can use
+    to add special effects like TV scanlines to its video output,
+    or smarter algorithms for scaling up to modern PC resolutions.
+    See "Installing custom shaders" below for details.
+  - [Mercurial Magic](https://github.com/hex-usr/Mercurial-Magic/)
+    is a tool for converting MSU-1 games and mods into a format
+    higan can use.
+    See "Importing MSU-1 games" below for details.
 
-- the most important higan forks?
+There are also other projects
+based on current or older versions of higan,
+in whole or in part,
+that you might want to check out.
+
+  - [Mednafen](https://mednafen.github.io/)
+    is another multi-system emulator.
+    Its SNES emulation is based on bsnes v059,
+    from the time before bsnes was renamed to higan.
+  - [BizHawk](http://tasvideos.org/BizHawk.html)
+    is another multi-system emulator,
+    specialising in the creation of
+    tool-assisted speedruns.
+    Its SNES emulation is based on bsnes v087.
+  - [nSide](https://github.com/hex-usr/nSide)
+    is a fork of higan that greatly enhances
+    its NES emulation support,
+    and adds minor features to the other cores too.
+    It also restores the "balanced" SNES emulation core
+    that was removed from higan in v099,
+    which is less CPU intensive
+    than the current accuracy-focussed core.
+  - [bsnes-plus](https://github.com/devinacker/bsnes-plus)
+    is a fork of bsnes v073
+    that adds improved support for debugging SNES software.
 
 Installing higan
 ================