Five most valuable OOP eyepieces

OOP = Out of Production.

What are the five most valuable eyepieces types,
of the eyepieces that are out of production?

I speaking about eyepieces you'd observe with,
not 17th century Huygens which may be valuable,
but not as observing eyepieces.

Near as I can tell, it's these:
1. Pentax XL series 60mm giant eyepiece.
2. Leica 30mm 80 deg. 2"
3. Zeiss Abbe ortho 1-1/4"
4. Original Zeiss Monocentric
5. Pentax SMC ortho.