Example 1: Extra pictures/icons
For example, I would pay say $1/month per extra icon or perhaps just pay $10/yr for an extra 10, etc.
Example 2: Extra pre-built styles
I would pay somewhat extra for access to some additional styles that have been tested and debugged like the built-ins, etc.
Anyhow, those are just two I can think of that could be fun for users and raise some incremental cash.
