I believe event registration forms may already work this way, so should be possible to display any selections donor makes to custom field within an online giving form when sending notifications to staff. Because of long standing set-up, certain funds are not set up as funds so we can't select them as Designations on front end. Would like to have custom field table on form and show donor selection from that table when sending email notification to staff.

Found similar idea after submitting if you would like to merge the two concepts:
https://renxt.ideas.aha.io/ideas/RENXT-I-6933