Annotator is a Chisel plugin that allows you much greater leeway with where annotations show up. You can make them appear in unexplored areas, you can make them appear only after certain areas are explored... and to a limited degree, you can play with font color and size. This plugin is also available as part of the Chisel 2.1.6-enhanced package.

Merge is a Chisel plugin that lets you combine two marathon maps. This means you can actually work on complicated but repeated sections separately, and merge them in where you need them. (Good uses are airlocks, signature term areas, and anything else you can come up with.) This version fixes several bugs, and should now be quite useable. This plugin is also available as part of the Chisel 2.1.6-enhanced package.

Polygon Converter is a Chisel plugin that allows much more logical remapping of M1 to M2 or Infinity polygon types. This plugin is also available as part of the Chisel 2.1.6-enhanced package.