Situations are different but thinking of what has gone over well in the past. Anytime fruit is nice. A bag of tangerines, oranges, pears, the ladies appreciate the simple gesture and share around the house and also say so and so gave this to us. Same thing for chocolates. If you know the house well and its not a busy time, particularly during holidays, bring a bottle of champagne and keep a glass for you and the provider and give the rest to mms for the ladies. Not everyone is a big drinker, but some are and will enjoy it. In all of this, the girls talk and say who brought the goodies and thus you get street cred.
During your sessions in normal chit chat, tell your provider I like X,Y&X type food, what do you like? Most likely they said they like X, Y or Z too. Then offer to take them to that type of dinner when it is slow, or give them a gift certificate. Either way a step up in bucks but appreciated. I once gave a gift cert for a nice restaurant for all the ladies in a house thinking they would go or order take out if too busy. Turns out they invited me to go to because their English was so so and they wanted me to go help order and have a good time too. Ok, me at table with mms and 7-8 gorgeous K-gals, I got some strange looks but well it was fun.
Since being in the house all the time is boring, other things work too but border on relationship so be careful if that's not for you. Like, oh, you like the beach or casinos or whatever?, yeah I'm thinking about going next month let's go. (watch out for degenerate gamblers.) Often the ladies are not as mobile or as adept in English or American things, so they are happy to get away with a "guide" and worry free transport. Girlfriend to go, for the cost of a simple vaca, near or far. Remember, no visa/green card issues to fly within the US.
In the end, something to remember is the boredom of being in the house all the time, the often lower mobility of the ladies and the fact they are in a strange land. Anything that alleviates one or more of these is often a welcome distraction from the day in and day out of the business.
Happy gifting.