Extensions ecosystem

Draw byte field diagrams using bytefield-svg.
github.com/Deep-Symmetry/bytefield-svg

Render charts using Chartist.js.
github.com/mogztter/asciidoctor-chart

Render color chips for a given color reference (either a name, rgb, rgba, hsl, hsla or hex reference)
github.com/mogztter/asciidoctor-color

Convert diagrams to images using Kroki.
github.com/mogztter/asciidoctor-kroki

Inline macro to render emoji:heart[] as an <img> that points to a remote SVG using Twemoji from Twitter.
github.com/mogztter/asciidoctor-emoji

Transform AsciiDoc code listings into interactive playgrounds which run in the browser. Add the %interactive option to your [source] block.
github.com/oncletom/asciidoctor-extension-interactive-runner

Server-side mathjax rendering into inline svg.
gitlab.com/djencks/asciidoctor-mathjax.js

Nest open blocks to any depth using a block macro, at least until the spec allows this directly.
gitlab.com/djencks/asciidoctor-openblock

Render PlantUML, Ditaa and Graphiz (DOT) diagrams as PNG or SVG using a PlantUML server.
github.com/eshepelyuk/asciidoctor-plantuml.js
No longer maintained. Consider using Kroki instead.

Query an external json document or (in Antora) the Antora content catalog and render the result as a list, table, count, or repeating template block.

Define a block or inline template and "call" it with "variables", with the result isolated from the main document: that is, the attributes do not leak out of the template.
gitlab.com/djencks/asciidoctor-template

Render tweet using the Twitter API. Use the tweet macro with a tweet id: tweet::1041369960436703232[].
github.com/mogztter/asciidoctor-tweet