Sub Alerts bookmark
I notice a lot of streamers who are unsure if they missed subs while they were in game. Some using timers and the delete option for check marking them as they go (Fed's subathons) or simply hoping they got everyone after listing some.
I think a nice small feature would be some way to keep track of mentioned subs on the regular alert box would help a lot. Maybe just an arrow or selection or coloring coding thing.