HackMD has lots of icons ( :iconname: ) and 5 kinds of triple column blocks.
:::danger
messages in red background color block
:::
:::success
messages in green background color block
:::
:::info
messages in blue background color block
:::
:::spoiler
messages in an expand/collapse-able block
:::
:::warning
messages in yellow background color block
:::
HackMD has lots of icons (
:iconname:
) and 5 kinds of triple column blocks.