Microsoft Project has custom fields on task level (and resource level as well). The last version I worked with (2011) had something like 30 text fields, 30 number fields, 30 date fields, 30 flag fields etc.
On project level, these fields could then be used individually, i.e. project 1 might use TextField1 for some notes, project 2 use it for a pulldown list with a selection of items, project 3 for a text string calculated by some formula.
Is something like this available in Jira?