There are many National Standards, but overall the International Organisation for Standardisation, based in Geneva, Switzerland has established tens of thousands of standards covering almost every coneivable topic. Most of these are then adopted world-wide replacing all the incompatible 'home-grown' standards. Many of these standards are naturally evolved from those designed in-house within an industry, or by a particular country, whilst others have been built from scratch by groups of experts who sit on various Technical Committees.
The [ISO Web Site] describes more of the work that ISO does. Many ISO Standards are used within the Internet... the most well-known being ISO 8601, ISO 3166 and ISO 8859.