Can anyone think of particular thematic material for Investigators to start with in addition to their current possessions. I appreciate that every freebie boosts certain investigators to some extent but I'm more interested in theme than balance.

So far I've got the Private Detective with the Private Detective cards, the Student with Miskatonic student, the professor with Miskatonic Almnus and the Psychic with the Psychic cards. Have I missed anything obvious?

There is a bunch of material Tibs worked on some time ago. I'll drop you the pdf by email (now, I think, if I'm able to find them in my HD ::laughter:

Here's a link to the BGG page with the files:

www.boardgamegeek.com/filepage/63297/thematic-starting-possessions

You either need a BGG account, or to solve a Captcha to download them.

Here's the Introductory Expansions variant, too:
www.boardgamegeek.com/filepage/69008/introductory-and-expansion-scenarios