The basic premise in this timelines the microstates and other geographical fragments play a greater role than in OTL - where their significance tends to be marginal (with the possible exception of the Vatican) and where many were incorporated into other states.
A few examples are listed below - which can be developed according to individual interest. .
Danzig remains independent of Poland - so the Solidarity trade union emerges elsewhere in Poland (and Lech Walesa does not become President)
D'Annunzio retains control of Fiume
Moresnet has already been described here.
The Orkneys and Shetland Islands – originally transferred to Scotland in lieu of an unpaid dowry – gain a degree of autonomy and provide a ‘leakage route’ across what are now EU borders.
Tannu Tuva is described on that page.
Trieste and West Berlin develop as gateways between Eastern and Western Europe.
The Walled City between Hong Kong and China was in administrative no-man's-land: more of these come into existence.
Microstates exist in sufficient number (and at various levels of notability) to have their own wiki in OTL.. In this ATL a number become more prominent and achieve notability on the international stage. Rather than subject themselves to the full legal etc rigours of statehood, they develop the equivalent of commercial limited liability, cooperative societies and similar bodies.
Mosaicworld (eparation point the Middle Ages).
The small states (cities, lordships, principalities, domains, religious houses etc) do not fuse into larger, unitary entities as in our timeline. Such larger entities as emerge are of a more cooperative nature - resembling, for example, present day Switzerland. The Hanseatic League and similar bodies develop (perhaps including rivals to the Thurn and Taxis postal system). Dynastic marriages tend to lead to transfer of territories rather than unification. Larger state-entities do emerge but due to historical regional traditions tend to have far more devolved power and regional parliaments than in OTL.
The Reformation takes place, as in OTL, following the principle adopted in some areas of Europe at the time of 'As the ruler so the people' - which can lead to tensions as skilled/more mobile sections of the population whose belief system is at odds with their ruler's move elsewhere. The rulers have to decide whether to accept the removal of troublesome sections of society is worth the loss of skills arising.
The age of expanion proceeds somewhat differently to OTL. Exploration and trade occurs as in OTL, but with a greater degree of cooperation being accepted: the European traders cannot 'call in the gunboats' so readily. As the Europeans are used to confederations whose components can operate according to quite different legal and other systems, they are willing to operate on such a basis with local equivalents, the ruling classes and traders of which are willing to coopt what is being offered. The Americas develop as a number of smaller states, in which indiginous populations have a greater prominence. Imperialism as we know it does not occur - but refers to a series of tied economies amd more proxy wars.
The industrial revolution occurs but at a much more piecemeal rate - there is less pressure for large scale mass production. Those cities and areas where industrialisation occurs press for greater autonomy.
WWI does not occuror has a much more limited impact and the dictators of the 20th century remain marginal figures.
Departure point - late 18th century. Various factors common to our timeline: American and French Revolutions, the events in India following Aurangzeb's death, economic decline in China, pressures in Latin America leading to colonial declarations of independence, effects of Russo-Turkish war etc) have a somewhat different impact to OTL leading to what we would term devolution. There are various consequences. Napoleon rises but cannot create a Grand Army and so his ambitions are reined in. The sometime colonies and 'regions defined' in North America have greater autonomy - which has an impact on the ending of slavery. In OTL England's industrial north had, prior to the 1830s little representation in Parliament, while other areas of historical significance which had declined, retained their representation. Rather than press for a Reform Act inhabitants of this region work for a regional parliament in line with the Scottish and Irish Parliaments - the southern part of England becomes a relatively backward part of the UK until the service industries are developed. France becomes a confederation. Industrialisation occurs to a far greater extent than in Mosaicworld. What in OTL is called the West Lothian Question occurs in various forms and is given a more generic name.
There are also more middling sized and small states than in OTL (Georgia remains independent of Russia; Poland becomes a fragmentary state etc). WWI gives rise to more Moresnet-like and Andorra-like entities - thanks to the choices available on the various plebiscites. Several of the dictatorships of OTL emerge, but, given that they have to deal with greater regional autonomy their careers follow quite different paths.
In both cases international organisations develop. In those cases where the purpose is purely practical - agreements on longitude, the law of the sea etc - there is little difference to the equivalent in OTL (with, in some cases, allowances being made for 'functional entities' - eg the Universal Postal Union having to deal with the Thurn and Taxis postal network, and the external Post Offices established by certain states abroad). In other cases the structure is quite different: in Mosaicworld the practicalities of coming to agreement among 500 states, and in Fractalworld of balancing out the requirements of states in a range of sizes. When the United Nations in OTL was established what was then the USSR was allocated three seats, and the US was offered, but did not take up, a similar concession: while various parliamentary bodies divide up their membership according to the population of the component states: such phenomena might occur more frequently in the international organisations in Fractalworld.
In both cases notable political theorists of OTL emerge - but the views presented are somewhat different. Karl Marx, for example, among his voluminous (and sometimes not mutually compatible) writings, is in favour of devolution of political authority.
- Brussels (Rise of the Statelets)
- City State (Rise of the Statelets)
- Federal States of North America (Rise of the Statelets)
- Haute Savoie and Gex (Rise of the Statelets)
- International organisations (Rise of the Statelets)
- Moresnet (Rise of the Statelets)
- Multinational Companies (Rise of the Statelets)
- Railway States (Rise of the Statelets)
- Seagoing entities (Rise of the Statelets)
- Tannu Tuva (Rise of the Statelets)
- Transiberian Railway Free State (Rise of the Statelets)
- Vatican City