1) First-aid kit and medications: If someone is traveling internationally it is always advised to visit any hospital or health center and getting vaccinated against any local disease. Even for shorter travels, it is mandatory to carry medical items like a first aid kit which will comprise of an antiseptic liquid, band-aid, scissors, cotton, wrapping bandage for any unseen cuts and injuries and thermometer. Other than that medicine like antibiotics, antacids, vitamin, calcium, and other mineral supplements, allergy medicines, paracetamol must also be carried.
2) Additional items: Excluding all the other aforementioned items some other things like torch, hand sanitizer, napkins, tissues, knife, sunglasses, Bluetooth speakers, USB cables, camera, charger, multi-purpose chargers, adapters, spike busters, towels, sewing kit, shaving kits, mirror, towel, maps, etc. are some absolute essentials.
3) Essential travel documents: Carrying personal id, credit card, debit card, health insurance documents, travel insurance, itineraries, passport, visa, etc. are also mandatory.
To conclude, for traveling safe and sound one must carry all the items that are mentioned. Any unseen circumstance might come up, and we must always be ready to face it.