There are smaller good first issues, and here is a list of larger projects that could be done in pandoc:
Use Text instead of String throughout. This would involve API changes and extensive (but not too difficult) changes to pandoc-types, pandoc, texmath, pandoc-citeproc.
Improve table type to allow col/rowspans and possibly other features. Modify readers and writers to handle the new features. (See #1024) (For individual readers and writers see #6311, #6312, #6313, #6314, #6315, #6316)
Improve handling of figures with a new Block-level element. (See #3177)
Explore allowing attributes on all elements. (#684)
Create a flexible system for labeling objects (images, tables, code) and referring back by number and/or link. Or, more minimally: handle \label and \ref better when parsing LaTeX. (See #813, #165)
Automatic identifiers for images and tables in HTML output. (#208) Must take care not to break existing documents relying on automatic identifiers for headers. (See also #1806.)
Syntax and (block or inline?) element for anchors (see #1299, #1621, also http://talk.commonmark.org/t/turning-empty-link-definitions-into-anchors/893).
Integrate pure Haskell commonmark parsing library (jgm/commonmark) when it's ready, replacing the existing Commonmark module which relies on a wrapped C library and doesn't handle extensions well. (This will take care of a number of issues, including #1735)
Add a ConTeXt reader (#1423) -- should be possible to modify the LaTeX reader.
Add a plain TeX writer (#1541).
Make Format an enumerated type (#547).
It would be great to have number 5 standardized. There are several workarounds out there making things complicated.
Maybe pin this issue?
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It would be great to have number 5 standardized. There are several workarounds out there making things complicated.