Thanks! While the app can't do that right now, what you CAN do is... make a copy of the free BitD airtable databases and add the characters that you find most interesting there. It is a relational database so you can map NPCs to factions. You can create a faction for the PCs and link interesting NPCs to it.
A much simpler, and more limited, solution is to use ScoreRunner's (super-charged google-sheet based character and campaign tracker) GM and Crew tabs to mark down interesting NPCs.Blades
'68 looks pretty awesome. If someone wanted to, they could clone ScoreRunner and start adding Blades '68 content to it.