Endless wishlist for really old stuff… I’d like to try Lilienthal’s glider, set off at 200 Ft and see if you can land it on the ground safely… guess that is out of scope for FS2020…
Haviland Comet is available for FSX, would love to try it.
Sky writing… there is a smoke switch on Carenado YMF-5, but it does not leave any smoke 
& what about SE 5a, plane used in WW I
thx pinterest - Royal Aircraft Factory S.E.5a' British fighter 1918 | Modellbau flugzeuge, Flugzeug, Geschichte
There is a lot of funny stuff at http://smm.solidmodelmemories.net/