If you are willing to donate the timetables then timetableworld would be a good home for them. They scan the timetables and put them on a website which anybody can access without charge. I suggest you list what you've got and get in contact with the website owner.
There are a number of companies that buy and sell that sort of thing, or that organise auctions. They can probably found via an internet search, but it may be easier to buy a copy of the Railway Magazine and look at the adverts in the back pages.