If you have a 501.c3 write out a grant proposal. there are many corporations that wuld love to give in kind gifts or give money to cover knives if the proposal is good enough
There are MANY working chefs that have used knives, even band new knives they don't use, that we've acquired as test samples, that we've bought with the intent to pass on. But we generally are going to donate to the culinary schools and to non-profits. I give out about 6 a year.
As far as selling used equipment, there are probably a hundred places in the bay area. Look up "restaurant supply". Many sell used big equipment, hotel pans, or "mass furnishings" (silverware, plates, table linen, etc) or they can refer you on. We have probaly about 2 dozen in phoenix. Also Auction houses. Restaurants go out of business all the time and you can buy at auction
As far as selling used knives. Craigslist, Chef Talk used to have a "for sale" forum. I know chef knives to go has a used "for sale forum"