Very often those running events are doing so because of their commitment to the charity rather than because they are experienced managers. A Toastmaster can be very helpful as he or she will have experience gained from involvement in many charity events and will have proven suggestions for fund-raising.
In particular, a Toastmaster may do well running a charity auction. Professional auctioneers are used to selling to an audience who know all about the sale items and are there explicitly to buy, whereas a charity auctioneer often has to work hard at describing and “selling” the lots, then cajoling the audience into parting with as much money as possible - possibly far more than the item's 'market' worth.
A Toastmaster can:
Receive and direct your guests as required
Liaise with event photographers and videographers
Announce luncheon or dinner and direct guests to their places
Introduce speakers and entertainments
Organise “ice-breaker” and other fund-raising amusements during the event
Manage the drawing of the raffle and announce the winning numbers
Act as auctioneer
Conclude the formalities and announce totals raised