Fields Per Blog Post Type
Custom Fields has the ability to limit the visibility of fields to specific blog types. This is handy if you want to cleanly segregate fields for your administrators when they edit blog posts.
Configuration for this can be found on the settings page for each field within the Blog Post configuration section in the app.
Click Edit on any Blog Post field then scroll to the bottom of the page and click on Additional Settings. By default, new fields associated with blog posts will be set to show on all blog types. All blog types will be listed in the settings and you can limit the visibility to only certain types.
If you're expecting to see blog post fields but aren't, check the Visibility Settings on those fields. This can be a source of confusion during launches for stores that use a development -> staging -> production workflow and synchronize fields but forget to check these settings after launch.