Hey there Roland. Thanks for the note here, and for reaching out. You are correct that the recurrence patterns available are at this point limited to the options under “Custom.” We introduced recurrence as a 2.0 feature, and since then the most requested addition from the community is what you’ve noted here: more random recurrence patterns. We’ve got those in the works and are planning to introduce some new ones in 2.1, which will be out this summer.
In the interim, unfortunately, random recurrence patterns will have to be “faked” using the current limitations. Hope that helps and sorry I couldn’t offer up more. Let me know what else I can do.