Some members of my group, myself as the main writer have a shared One Note file that has the journals of those that write one.
Our Troll Beastmaster decided that his form of a journal would be a beastiary, where, his ideas of strategy to fight them, and in which we also record any stats we gain from Creature Analysis. (my Windling Windscout tends to leave foot prints all over it when she adds her own notes
)
Our Obsidiman Troubadour also keeps a poetry journal from the stories and songs she sing and learns.
My Windscout and our Elven Nethermancer keep a Potions and Poisons Books for the concoctions we know (we both have Alchemist)
I keep my Map case in there from the Maps drawn along the way.
There is also a section of Thread items we have gathered along the way along with what we have learnt about them.
We also keep a section on the Characters we have met along the way, NPCs, Masters, helpful innkeepers etc. what their feelings towards us are and if they are adepts what type and circle if we know or an approximation of we don't