Ah that's cool, I didn't realise that you had family connections in Iran.
With 100k USD, I imagine that you could start most kinds of businesses! The obvious answer would be an IT/online business, especially seeing as that is your current line of work, which would probably take much less capital.
I'm in a similar situation myself where I've successfully transitioned from being employed to being a freelancer and am now looking to move on and create a proper, scalable business.
Since working online, I've lived in Manila, the capital of The Philippines, and here are some observations I've made about starting a business here if you're interested... I'm sure a lot of these observations could be applied to other developing countries too.
There are a lot of Australians, Americans and Europeans who run IT and internet businesses of every kind here who have their clients back in their home countries. The clients pay Western prices for the services and have a familiar voice to talk to but then they have their employees in the Philippines (which the client may or may not know) do the actual work, paying them 20,000 pesos or so a month which is a respectable wage here but probably at least 1/5 of what it would cost to hire a similar worker in Britain/Australia/USA. Everybody wins and it is a great business model, especially if you already have relationships with people back home who you think you could sell an IT service to.
There are also a lot of Chinese and Korean run online casino companies which could certainly be very lucrative but I don't have the expertise to do it and it's not exactly a field where trial and error is a sensible idea.
Aside from online businesses doing the work in the Philippines but catering to foreign customers, there is also a huge amount of potential for creating an online business, website or app for the Filipino market. Filipinos still don't really use the internet for most day to day things (eg shopping, buying tickets, watching movies) the way that we have done for many years in the West but that shift is happening. If you think Westerners are glued to their smartphones, Filipinos will blow your mind! There are very few good existing websites here and the few decent ones that there are are still generally more expensive and more hassle than doing the thing the old fashioned way (eg going to the shop, phoning a hotel, hailing a taxi). If you can get in and establish yourself as a market leader now (whilst there is not really any competition) before the shift truly happens, you'll be rich by the time the Philippines goes online.
The market is still so undeveloped that even if you don't have a good original idea, you could be successful just ripping off the popular websites in Europe or America and many people already have been. I'm not suggesting you do this but am just telling you to show how much opportunity there is. A few examples are "Grab", a watered down more expensive rip off of Uber which is so popular here and recently secured $750 million funding. Another is "Lazada", a watered down, more expensive and clunky rip off of Amazon which has got around $600million funding and I think was started by a British-Arabian guy. Another is iFlix which is a shameless rip off of Netflix but has received around $50million funding and was started by an Australian guy.
However, it is very difficult to own a business as a foreigner in the Philippines unless you are married to a local so a lot of these types of businesses are in a grey area legally (read: technically illegal under Philippine law). On the other hand, the government doesn't mind and likes the foreign investment so they have a lot of loopholes which will let you do it (eg. unlimited stay/renewals no questions asked tourist visas, easy no questions asked banking, cash payment for rentals of offices etc).
For the reason above, you'll probably be limited to running an online business here but there is also a lot of potential for brick and mortar businesses too if you can find a way to do it within the law.
Western food and snack cafes and restaurants and fast food places are extremely poplar here and generally cost almost as much as they do in the west to buy things from (maybe 60% of the price on average). However, the wages, rent and overall running costs of these businesses are much lower than in the West so I image the profit margins are much higher!
If you're just starting an online business and looking for inspiration, I would recommend going to co-working offices. You'll people, foreigners and locals, who run online businesses in the country of your interest.
That's a brainstorm of my thoughts on running a business in the Philippines, and probably to an extent elsewhere in the developing world! I hope it was of some help