Where to Get Ghost Themes
A comprehensive list of links to premium and free Ghost themes . . .
GitHub
ElectronThemes - Ghost Blogging Themes
Themeix - Ghost Themes Archives
GumRoad Marketplace - Ghost Themes
Haunted Themes - Premium Ghost Themes
Frank Theme - Free Ghost Themes
GTheme - Popular & Best Selling Premium Ghost Themes | Ghost Themes and Apps Marketplace
Stylesheets.dev | Beautifully designed Ghost themes for whatever you're building
Creative Market ~ Ghost Themes
Biron Themes - Best Ghost Themes
Golem - Premium Ghost Themes by golem.io
ThemeSpectre - Free and Premium Ghost Themes
Fueko - Premium Ghost Themes by fueko
Super Themes Co. - Ghost Themes
HTML5up.net - Ghost Themes and Templates
Hostinger - 15 Free Ghost Themes (Article)
Make A Website Hub - Best Themes for Ghost Platform - Free and Premium 2019 (Article)
Webdesigner Depot - 10 Free Kick-Ass Ghost Themes (Article)
Colorlib - 28 Best Free Ghost Themes With Simplicity In Mind 2020 (Article)
Wow Themes - 10+ Ghost Blogging Themes (Article)
Design Shack - 30 Beautifully Designed Ghost Themes (Article)
ThemeFunace - 50+ Best Ghost Themes for Simple Clean Blogs 2017 (Article)
Vanila Blog - 10 Free Ghost Themes (Article)
Codester - Top 20 Ghost Themes 2019 (Article)
WinningWP - 35+ Superb Free and Premium Ghost Themes for 2015 (Article)
SpeckyBoy - The 15 Best Free Minimal Ghost Themes (Article)
WebDesignDev - 20 Free Ghost Themes with Minimalist Designs (Article)
85ideas.com - 10+ Best Ghost Themes (Article)
EGrappler - 25 Free Themes for Ghost Blogging Platform (Article)
CodeCondo - 12 Free Minimal Ghost Themes (Article)
HaeckDesign - Top Free Ghost Themes & Ghost Skeletons | Freebies (Article)
DesignHooks - 50+ Free Ghost Themes 2019 (Article)
Buildify - 13 of the Best Portfolio Ghost Themes (Article)
Theme development
Ghost themes are written with a templating language called handlebars, which has a set of dynamic helpers to insert your data into template files. For example: {{author.name}} outputs the name of the current author.
Ghost has full and extensive theme documentation which outlines every template file, context and helper that you can use. You can also get started with the useful starter theme, which includes the most common foundations and components required to build your own theme.
If you want to chat with other people making Ghost themes to get any advice or help, there's also a themes section on the public Ghost forum.
And some websites about building themes:
Webflow to Ghost | Build Ghost Themes totally in Webflow
Dan Rowden - Product Builder | Subscriptions, Newsletters & Marketplaces
Dana Hooshmand | Build Anything
Grant Winney | 5 Quick Hacks for your Ghost Theme
Shared Physics | Working With Ghost
How to Create Ghost Themes: Introduction - YouTube
Paolo Tagliaferri | Software Architect
Some of my personal faves on ThemeForest:
https://themeforest.net/item/docslab-a-knowledge-base-and-documentation-ghost-theme/28726955
https://themeforest.net/user/pxthemes/portfolio
https://themeforest.net/item/floro-responsive-gridalicious-css3-ghost-theme/7127851
https://themeforest.net/item/nuevo-a-timeline-for-ghost/6888181
https://themeforest.net/item/phantom-responsive-parallax-theme-for-ghost/6836135
https://themeforest.net/item/quill-minimal-blog-and-magazine-ghost-theme/19623926
https://creativemarket.com/pixelandkraft/203888-Archster-uniquely-powerful-layout
https://themeforest.net/item/athena-modern-ghost-theme-with-masonry-layout/22751436
https://themeforest.net/item/valkyrie-a-highly-visual-ghost-blog/22576630
https://themeforest.net/item/whie-minimal-ghost-theme/22547593
https://themeforest.net/item/breek-a-masonry-theme-for-ghost/13112831