Lots of these have already been covered, but in the past, I've brought pencils, colouring pencils, stickers (very popular), Canadian souvenir-type things (hats, etc...), hair accessories, gardening gloves for the gardeners (who work long hours and don't get tips like the chamber maids and restaurant staff do). Children's/babies' accessories like soothers and children's tylenol are also very much appreciated. Staff also appreciated getting advil/tylenol or toiletries.
A lot of the women like colourful tights/nylons or fishnets - especially if they are patterned.
Anyway, just my two cents. They are always very appreciative of anything you do give them and to me, the service is so outstanding, it's the least I can do to recognize it.