These filter options would appear under Clients - Filter Icon, correct?

Some questions for clarification

Product/Service filter. Are you looking for a particular package name or service meta data? Under a client's profile page the services filter has "Package Name", and "Service Meta" as options. If the client has a package called "Bronze Hosting" and it's used for "domain.com", the package name would match the Package Name search, and domain.com would match the Service Meta. Or are you thinking both of these options? I don't think we would combine them into a single field.

Payment Method. Do you have in mind the "Payment Type" filter that exists under Transactions filter? So you could filter by clients that have made a payment with one of the options listed there?

Absolutely spot on!

My main aim would be to filter by a specific product/payment type/currency when looking at clients - A combination of the same filters for:

*Package group filter for package or module on /admin/plugin/mass_mailer/admin_filter/

*Payment type on the transaction list would be perfect just to help see things a little clearer!

Added to client view would be nice to be able to quickly see figures across multiple products