When the technology improves sufficiently maybe there will be a drone the size of a dragonfly that land on targets and inject them with ricin or another poison.

When the technology improves sufficiently maybe there will be a drone the size of a dragonfly that land on targets and inject them with ricin or another poison. That requires a lot better targeting than a plastic container loaded with explosives and ball bearings, which just has to get close to the target. Still, it would make a great assassination tool.