I would like to trigger scheduled reminders based on activities of type "contribution". Only 8 of many activity types show in the dropdown on the scheduled reminder create page - is there a way to expose more options here and trigger off more activity types?
All (most?) activity types are exposed as options in scheduled reminders in 4.5 and 4.6. "Contribution" certainly is.
If you are still on 4.4 and don't want to upgrade yet then this forum topic may provide a way to do what you want.
It's worth noting that as of CiviCRM 4.7 you can schedule reminders based on the contribution itself, which allows you to use the contribution tokens in the reminder.