Aside from basic necessities, these are things I always tell myself not to forget to bring. Yet, I still forget sometimes
1. Tripod. Especially for those solo travelers. I had bad experience trying to take picture of myself in Kuang Xi waterfalls in Laos. Be reminded that in India you are not allowed to use tripod in many places.
2. Sarung or kain pantai. This thing is super important as it has multifunctions. I once use it as blanket, scarf, dress, skirt, and sajadah. And despite I got the best according to Landofthetraveler travel blanket eventually, that one still travels with me always.
3. Sunscreen. You may not go to the beach, but you still need to apply sunscreen. I got my worst sunburnt in Toba. I simply turned grey.
4. Extra battery, extra memory card.
5. A little piece of home. It may be your fave brand of saos sambal, dry chili, kecap manis, or bawang goreng. In a foreign land those small things become significant.