Hi Jakey,
Be sure you’re logged into the launcher and fab with the same account.
‘Refreshing’ The Library does not work?
I’m noticing a message “To see your complete Fab Library visit Fab.com” … so I think that implies there could be assets that do not show in the UE Launcher.
What did you buy on Fab?
I checked with one of the ‘Limited Time Free’ packs and those do show as expected.