I take mosquito plug ins ( one for each room)
I take mosquito, fly and wasp room spray, and spray under all furniture, in wardrobes and in all rooms on arrival and before putting clothes away (you would be surprised how many dead bugs that fall onto the floor after using it)
my logic is that during a room change over housekeeping open all windows and doors letting the little biters in!
Zip locker bags to put dirty knockers and socks in, and decant febreeze into a small spay bottle to keep my suitcase fresh.
Antiviral and antibacterial spray - I go over door handles, remote controls and light switches mini fridge which may be full of germs. (decanted into small travel spray bottle)
Disposable shower caps - I use them on shoes before packing them.
I decant some washing up liquid into a small bottle- I may be all inclusive, but washing up tea / coffee and glasses in the room is useful, but an entire bottle is too much if you buy it when you get there.
Silk pillowcase - reduces frizzy hair from the heat / air conditioning.
reuseable canvas bags in hand luggage for aeroplane duty free
Coffee bags and tea bags (I like particular blends)
Disposable facecloths
face sheet masks (I keep them in the fridge)
3 of those wire triangle hangers - so that you can steam clothes while you have a shower to get the creases out - hotel hangers always have fixed hooks in the wardrobe.