I don't know specifically about on Dragonflys, but I've met the 1/4 and 1/8 inch BSF types.
I don't know about obtaining the original types, which are about useless in my estimation,
but you can buy more modern types which a modern grease gun can latch onto, and apply PRESSURE.
I have heard that applying some cloth over the old type will avoid a mess and apply some pressure,
but have not tried it.
Be aware there are also 1/4" UNF type grease nipples, and I think a similar metric equivalent.
You can also obtain stainless marine varieties, which keeps them nice and shiny.
If such things are important. But not in BSF sizes ... ?
There are also larger sizes. Much larger in industrial type stuff.
Hopethishelps.