All kinds of lists
A simple list is unordered and groups a set of related items. Any item may contain a sub-list.
Ordered lists group related items and mark them with ascending counters. They provide a very clear structure for a relatively short number of items.
Definition lists consist of terms as list markers, which are associated with details in the list entries.
A task list on a web page should be an interactive element which directly changes the corresponding Markdown. A theme can’t establish such a connection on its own.