What types of companies can be formed in Singapore as per the Singapore Companies Act ?

As per Singapore Companies Act, 1967 any person may, whether alone or together with another person, by subscribing his name or their names to a constitution and complying with the requirements as to registration, form an incorporated company. A company may be - a company limited by shares; a company limited by guarantee; or an unlimited company. No company, association or partnership consisting of more than 20 persons can be formed for the purpose of carrying on any business that has for its object the acquisition of gain by the company, association or partnership, or by the individual members thereof, unless it is registered as a company under the Singapore Companies Act, or is formed in pursuance of some other written law in Singapore or letters patent.