you can use things like Xpand!2 for brasses, Zenology for leads, Nexus for crazy pads, or you could find some one shot kits (you could get conz.xo trapties vol.1 kit)
i'm no expert or nothing but i saw this in another video: u can transpose multiple tracks at once when selected if u click on the menu (the little arrow thing) on the top corner of the channel rack