Hawker Hurricane. British fighter that due to its well known construction techniques made up the bulk of the RAF during the battle of Britain. Absolutely love the way they look and would love to fly one someday.
Blackbird is the 20th century’s crowning technical achievement. Nothing else comes close; not television, not plastics, not NASA, not the information revolution. Maybe scientific medicine, but that one is really more about disciplined clinical practice.
Mechanically in 5e, I enjoy the existence of the Ethereal Plane. It is kind of the planar goo that connects the other planes to the Prime Material one and allows certain classes to exploit the closeness between the planes. A good example is Blink and Etherealness, both which allows users to use the this plane as an escape from sticky situations and to do a little scouting without being detected. A good balancing counter is Forecage, which allows the caster to create a temporary prison that encompasses a certain section of both the Prime Material and the Ethereal Plane.
If using The Balance campaign , it also has the added danger of it being where The Hunger scouts reside.
I collect and restore (and use) these. Though I have nos 2-7 and some of the 1/2 sizes, the plane I use the most is the 102 size. If I were rich I would gladly trade some Stanleys in for a Norris smoother.