Some countries with large wealth, but make national income in strange and unique ways, not like most of countries in traditional labouring for state wealth. Some with its unique resources, some with the latest developing technique. And in history, some countries grabbed the wealth  with military force. Here are some examples lists.

1, Domains and IP. 
Tuvalu domains ".tv". Tuvalu,  with the Population of  10,472 (2010),  Government revenues largely come from the lease of its highly fortuitous .tv Top Level Domain (TLD); In 2000, Tuvalu negotiated a contract leasing its Internet domain name ".tv" for $50 million in royalties over a 12-year period. Domain name income paid most of the cost of paving the streets of Funafuti and installing street lighting in mid-2002.
IP address assignement.  The Internet Assigned Numbers Authority is a US-based organization tasked with overseeing the allocation of IP addresses, but in fact it is not assigned in a fair and consistent manner. Namely, some IP addresses are reserved for special uses and cannot be used for host, subnet, or network addresses. And more IP address were assigned to American ISP, caused lot of website owner to buy IP address and website in USA, hence more national income by American ISP.

2, Off-shore company (formation) registration and Tax - Haven.
In general, most of the off-shore company registration service offered by small countries or regions, with comptitive factors such as: Low to zero tax; Secrecy, the registration documents do not contain any indication as to the actual shareholders or the beneficial owners of the company; Fast registration service; Competitive Government license fees; No paid-up capital required; No limitation on authorized capital; No financial reporting; No limitation on shareholders, directors and officers; Anonymity; Cost of Operations. Even registration is open to company owner's requirement.
Some registry coutries (registration fee and limitation):  Seychelles $ 100 No limitation,  Samoa $ 300 $ 1’000’000,  St.Vincent $ 100 $ 100’000,  Dominica $ 150 $ 100’000,  Nevis $ 220 $ 100’000,  Belize $ 100 $ 50’000,  Anguilla $ 230 $ 50’000,  Bahamas $ 350 $ 50’000,  Cayman Islands $ 600 $ 50’000,  Panama $ 300 $ 10’000,  Cook Islands $ 300 $ 5’000. Other countries are: British Virgin Islands, Bermuda, Gibraltar, Hongkong etc.

3, Off-shore banking (financial center).
 The factors will be considered by investors to set up a bank account: tax-haven, the level of service, privacy, asset protection, secrecy. Most offshore banks are located in island nations, banking service income plays an important  roles in national income. The best countries and banking center with high reputation are: Switzerland, Bahamas, Panama, Luxembourg,  Liechtenstein,  Andorra, Belize, Monaco etc. Others are: Alderney,  Anguilla, Anjouan, Antigua, Aruba, Bahrain, Barbados,  Bermuda,  Botswana,  Brit. Virgin Isl,. Brunei,  Cayman Isl, Channel Islands, Cook Islands, Costa Rica, Curacao, Cyprus, Dominica Dom, Republic Dubai,  Gibraltar, Grenada, Guernsey, Hong Kong, Ireland Isle of Man, Jebel, Ali, Jersey, Labuan Liberia, Macao, Madeira, Malta, Marshall Isl,. Mauritius, Montenegro Nauru, Nevis, Niue, San Marino Sark Seychelles, Singapore, St. Kitts, St. Lucia , St. Vincent, Turks & Caicos USA, Delaware USA, Nevada USA, Wyoming, Vanuatu, Vatican etc.  For Liechtenstein in 1996, banking service contributed over 12% to the country's national income in terms of taxes and dividends paid. In Vantican financial revenune account for 40% of national income.

4, Donation and Aid, Charity.
The government for some small cuntries and poorest countries, mainly live on Donation and Aid. Tuvalu, whose official development aid made up 44 percent of national income in 2009, according to World Bank data.
Some small coutries use the political reason to get more donation and aid. For example, some pacific countries  and regions get income from Taiwan.
And the specical is Vatican, Holy See, the most weathy country, about 45% of national income comes from donation and charitable giving in Vatican. And aid accounts for 61% of national income in Micronesia in 1997.

5, Stamps and Coins.
A lot of countries get income from stamps and coins. Stamps and coins income accounts for 10% of national income in Liechtenstein. Other countries are: Tuvalu, Cook Islands, San Marino.

6, Gambling.
Moraco (Monte Carlo), Macao, Las Vegas (USA). Gambling income accounts 40% national income in Moraco (ever reached 70%), and 60% (ever 75% 2005) of government income in Macao.
And the top Ten Gambling Countries are (losses per adult, dated 2010): Australia $1,288,  Singapore $1,174,  Ireland  $588,  Canada  $568.
The largest online gambling operated by England.

7, Remittances of overseas citizen (Diaspora).
2006, Yemen account 9% of national income, Lesotho 24.1% of GDP, Haiti  17% of GDP, Nicaragua 14.4% of GPD, Salvatore 12.6 of GDP, Jamaica 11.7% of GPD,  Dominica Republic and Ecuador 10% of GDP.
America is the No.1 remittance out, the 2nd is Saudi Arbia
The largest income remittance coutries are (2011): Nigeria, India, China, Mexico, Pakistan, Bangladesh, Vietnam, Egypt and Lebanon.

8,  Entire country rental.
You can rent the country of Liechtenstein,  the entire country, cost $70,000 per night, and minimum 2 nights, with some service included.

9, Vessels registration.
Panama is the largest country worldwide in vessels registry. In 2008 more than 8100 ships, boats, and vessels are registered under the Panama flag, registrated as Panamanian vessels, fishing boats, yachts, cargo ships, and tankers. And it make national income as: Initial fees of almost $100 million, yearly registry fees of $25 million, ongoing legal fees of $8 million. In Oct of 2010 registry vessels reached 13202.
Liberia, the country has second-largest maritime registry in the world, with some 3000 vessels registered under its flag in 2008.
The other countries are: Cyprus, Somalia, Malta, Singapore, Morocco, Sierra Leone, San Marino, Costa Rica, Honduras and Lebanon, Marshall etc.

11, Fishing licenses.
Most small occean islands, special in pacific ocean islands ntations, with large ownership territaorial water, but less population., sale of fishing rights. One of them is Nauru..

12, Guano (bird dropping).
Phosphate, the phosphate is actually a composite of two materials which have combined and solidified over the eons: decayed oceanic microorganisms and bird droppings. Most of islanda nations export phosphate for income. Some of them are: Banaba, Nauru etc.
Guano mining expert income accounts most of the national income in Nauru.

The other national income of countries are: Rental for military base, Mercenaries, Invest Immigration, Visa and Passport issue, Space lanch center rental (russia pay rental 115 milllion USD per year to Kazakhstan), Montaineering in Nepal, Pole light for Iceland, Santa Claus for Finland  etc.