Once Gale has said he needs items, then it should say on their tooltips that he can consume them. There are genuinely loads of them: I think any named magical item will do. Perhaps you can share some examples of named magical items you want to keep that he won't consume, given it sounds as though you might have a bug.
The bard items are items that are most useful for bards given they help with inspiration. Eg there's one in a locked chest near Alfira in the druid grove.
EDIT: I just reloaded my earlier save from when Gale first asked me for items, which shows some of the many items I already had that he'd take, and you can see down at the bottom of the tooltip where it should say that he can consume the item. If you're not getting any of this, then perhaps you have a bug.
![[Linked Image from i.imgur.com]](https://i.imgur.com/gWBvTKI.jpg)