diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index fe9432f..480aeb7 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -7,6 +7,7 @@
 * Keep descriptions concise, clear and simple, and end them with a period / stop.
 * New categories, or improvements to the existing ones are also welcome.
 * Make sure your text editor is set to remove trailing whitespace.
+* Sort the items in each section alphabetically.
 
 ## Quality standard
 
diff --git a/README.md b/README.md
index 5430ff1..6cda1f1 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@
 
 [DragonRuby Game Toolkit](http://dragonruby.org/toolkit/game) DragonRuby Game Toolkit is a professional grade 2D game engine. It's tiny (~3.5MB), fast, and cross-platform (including consoles and mobile). The managing members of DragonRuby are Ryan C. Gordon (core contributor of SDL), Amir Rajan (critically acclaimed indie game dev), Aaron Lasseigne (author, presenter, and a powerhouse Ruby developer), and Alex Denisov (LLVM specialist).
 
-See [a 5-minute intro to DragonRuby](https://www.youtube.com/embed/DYBRzglsEzU)
+See [a 5-minute intro to DragonRuby](https://www.youtube.com/embed/DYBRzglsEzU).
 
 This list is a categorized community-driven collection of awesome [DragonRuby GTK](https://dragonruby.org/toolkit/game) example apps, libraries, tools, frameworks, software and resources.
 Sharing, suggestions and contributions are always welcome!
@@ -16,16 +16,24 @@ Sharing, suggestions and contributions are always welcome!
   - [Developer Tools](#developer-tools)
   - [Libraries, Frameworks and Wrappers](#libraries-frameworks-and-wrappers)
   - [Documents & Tutorials & Presentations & Videos](#documents--tutorials--presentations--videos)
-    - [Presentations](#presentations)
   - [Resources](#other-resources)
   - [Contributing](#contributing)
 
-
 ## Games
 
+* [DragonOS](https://dragonridersunite.itch.io/dragon-os) - Interactive showcase of open source games made with DragonRuby GTK
 * [Games made with DragonRuby on itch.io](https://itch.io/games/tag-dragonruby)
 * [Itch Dragonruby Game Collection maintained by Akzidenz](https://itch.io/c/1043933/dragonruby)
 
+* Open source games
+  * [Engine samples](https://github.com/DragonRuby/dragonruby-game-toolkit-contrib/tree/master/samples)
+  * [Crashball](https://github.com/awfulcooking/Crashball) by awfulcooking
+  * [Dino Jump](https://github.com/presidentbeef/dino_jump) by presidentbeef
+  * [Dragon Shooter](https://github.com/pusewicz/dragon-shooter) by pusewicz
+  * [Luckpaint](https://github.com/Rabios/luckpaint) by Rabios
+  * [Tank Vs Zombies](https://github.com/shanshaji/Tank-Vs-Zombie-Game-Ruby) by shanshaji
+  * [XENO.TEST](https://github.com/brettchalupa/xeno.test) by brettchalupa
+
 ## Apps
 
 * [chart-global-temp](https://github.com/jasemagee/chart-global-temp/) - A line chart showing global temperature written using DragonRuby
@@ -37,32 +45,39 @@ Sharing, suggestions and contributions are always welcome!
 
 ## Libraries, Frameworks and Wrappers
 
-* [Zif](https://github.com/danhealy/dragonruby-zif) - A Drop-in Framework for DragonRuby Game Toolkit.
 * [Draco](https://github.com/guitsaru/draco) - An Entity Component System for DragonRuby GTK
-* [Smaug](https://smaug.dev/) - Installation and package manager for DragonRuby
 * [LDtkBridge](https://github.com/LittleB0xes/LDtkBridge) - A bridge between LDtk (level editor) and DragonRuby
+* [Scale](https://github.com/DragonRidersUnite/scale) - Lightweight starter template with common helpers
+* [Smaug](https://smaug.dev/) - Installation and package manager for DragonRuby
+* [Zif](https://github.com/danhealy/dragonruby-zif) - A Drop-in Framework for DragonRuby Game Toolkit
 
 ## Documents & Tutorials & Presentations & Videos
 
+### Books
+
+* [Building Games with DragonRuby](https://book.dragonriders.community/) - Free book by Brett Chalupa on getting started with DragonRuby Game Toolkit
+
 ### Documents
 
 * [Ruby for Dragons](https://ejectdrive.com/Ruby_for_Dragons/) - Alternative community supported wiki
+* [Dragon Riders Community](https://www.dragonriders.community) - Community website with recipes, news, and more
 
 ### Courses
 
 * [DragonRuby Game Toolkit Tutorial](http://dragonruby.school) by WNDX School
-
-### Presentations
-
-* <s>[power-overwhelming](https://github.com/amirrajan/power-overwhelming) - A github repo used by Amir Rajan for his presentation at RubyKaigi 2019.</s>
+* [Interactive Online Fiddle Course](fiddle.dragonruby.org/)
 
 ### Videos
 
+* [Coding Workshop for Aspiring Game Developers](https://www.youtube.com/watch?v=S3CFce1arC8) by Amir Rajan
+* [DragonRuby Game Toolkit 3.0 Performance vs Unity](https://www.youtube.com/watch?v=MFR-dvsllA4) by Amir Rajan
+* [Game Development using DragonRuby Game Toolkit](https://www.youtube.com/watch?v=ILdmGv_PY-0) by Amir Rajan
 * [Intro to DragonRuby Game Toolkit](https://www.youtube.com/watch?v=DYBRzglsEzU) by Ryan C Gordon
 
 ### Written Tutorials
 
 * [Roguelike Tutorial](https://github.com/Craggar/dragonruby_tutorials) by [Craggar](https://github.com/Craggar)
+* [presidentbeef's DragonRuby Game Toolkit notes](https://dev.to/presidentbeef/api-levels-in-dragonruby-game-toolkit-4jb4)
 
 ## Other Resources
 
@@ -74,6 +89,8 @@ Sharing, suggestions and contributions are always welcome!
 
 * [DragonRuby Discord](http://discord.dragonruby.org)
 * [Forum on itch.io](https://dragonruby.itch.io/dragonruby-gtk/community)
+* [GitHub Topic](https://github.com/topics/dragonruby)
+* [Newsletter](dragonrubydispatch.com/)
 * [Stack Overflow](https://stackoverflow.com/questions/tagged/dragonruby)
 
 ## Contributing