docs: cleanup showcase

Author: jackyzha0

docs/showcase.md

@@ -7,27 +7,21 @@ Want to see what Quartz can do? Here are some cool community gardens:
 - [Quartz Documentation (this site!)](https://quartz.jzhao.xyz/)
 - [Jacky Zhao's Garden](https://jzhao.xyz/)
 - [Socratica Toolbox](https://toolbox.socratica.info/)
-- [oldwinter の数字花园](https://garden.oldwinter.top/)
+- [Morrowind Modding Wiki](https://morrowind-modding.github.io/)
 - [Aaron Pham's Garden](https://aarnphm.xyz/)
-- [The Quantum Garden](https://quantumgardener.blog/)
-- [Abhijeet's Math Wiki](https://abhmul.github.io/quartz/Math-Wiki/)
-- [Matt Dunn's Second Brain](https://mattdunn.info/)
-- [Pelayo Arbues' Notes](https://pelayoarbues.github.io/)
-- [Vince Imbat's Talahardin](https://vinceimbat.com/)
+- [Stanford CME 302 Numerical Linear Algebra](https://ericdarve.github.io/NLA/)
+- [A Pattern Language - Christopher Alexander (Architecture)](https://patternlanguage.cc/)
+- [oldwinter の数字花园](https://garden.oldwinter.top/)
+- [Eilleen's Everything Notebook](https://quartz.eilleeenz.com/)
 - [🧠🌳 Chad's Mind Garden](https://www.chadly.net/)
 - [Pedro MC Fernandes's Topo da Mente](https://www.pmcf.xyz/topo-da-mente/)
 - [Mau Camargo's Notkesto](https://notes.camargomau.com/)
-- [Caicai's Novels](https://imoko.cc/blog/caicai/)
-- [🌊 Collapsed Wave](https://collapsedwave.com/)
 - [Sideny's 3D Artist's Handbook](https://sidney-eliot.github.io/3d-artists-handbook/)
-- [Mike's AI Garden 🤖🪴](https://mwalton.me/)
 - [Brandon Boswell's Garden](https://brandonkboswell.com)
 - [Scaling Synthesis - A hypertext research notebook](https://scalingsynthesis.com/)
 - [Data Dictionary 🧠](https://glossary.airbyte.com/)
 - [sspaeti.com's Second Brain](https://brain.sspaeti.com/)
 - [🪴Aster's notebook](https://notes.asterhu.com)
-- [🥷🏻🌳🍃 Computer Science & Thinkering Garden](https://notes.yxy.ninja)
-- [A Pattern Language - Christopher Alexander (Architecture)](https://patternlanguage.cc/)
 - [Gatekeeper Wiki](https://www.gatekeeper.wiki)
 
 If you want to see your own on here, submit a [Pull Request adding yourself to this file](https://github.com/jackyzha0/quartz/blob/v4/docs/showcase.md)!