Customs rules mostly don't care that something is a gift; they care what the item is and its value. Clothing, books, toys, and ordinary cosmetics for personal gifting are generally unproblematic anywhere as long as your total stays within the passenger allowance. Sealed commercial cosmetics are fine in reasonable quantities; a suitcase full of them starts to look like trade.
The categories that cause trouble are the same as always: food items, especially meat, dairy, fresh produce, and homemade snacks, which face biosecurity rules; new boxed electronics, which often attract duty and questions; counterfeit branded goods, which can be seized outright; and anything containing wildlife products like ivory, coral, or certain leathers, which may violate international treaties regardless of value.
Quantity is the other axis. One of something is a gift; a dozen identical items is a commercial import in the officer's eyes. Check the destination country's customs site for its restricted list, and when unsure, declare and let them decide.