I'm in the midst of making a list of which pens (fountain) to keep in rotation and which get put back in storage. Interestingly, none of my US or European pens made it on this active list; only pens from the East.
One or two Caran d'Ache pens may make this cut but none of the Montblancs or Pelikans.
The current list includes fountain pens from Pilot, Sailor, Platinum, Danitrio, Nakaya and Eboya; more from Sailor & Platinum than from the others.
AbE:
Plain simple pens:
Sailor:
1911S
1911L
Pro Gear
KoP
KoP ProGear
Pilot:
845
743
Eboya:
Middle and Small size Natsume
Nakaya:
Portable Writer
Piccolo Writer
Platinum:
Akatamenuri Izumo
Fancier pens:
Danitrio:
Hanryo Tongue Cut Sparrow
Takumi Mountain Bird
Takumi Tsugarunuri
Sho-Hakkaku Ancient Flowers
Platinum:
Sandalwood Sea of Clouds Izumo
Ascending Dragon #3776
Sansui #3776
Cranes Modern