For transparency, here is a short overview of sponsors to MapComplete. This ties in closely to the history of the project as well.
There is a Liberapay.
NL-Net is currently sponsoring Pietervdvn as well for specific improvements.
The following organisations ordered a theme to Pieter Vander Vennet and thus sponsered the project. As these projects are finished, they have no relation with the project anymore.
Most recent projects are first:
See https://osoc.be/editions/2022/removing-obstacles-with-open-data
Antwerpse Zuidrand commissioned a map with playgrounds and hiking routes
OSM UK commissioned an address importer
Visit Flanders commissioned a theme with electrical charging stations for ebikes, benches, parks, playgrounds, ... and ordered the 'note import'-flow. For more information, see https://toerismevlaanderen.be/nl/pinjepunt
See https://osoc.be/editions/2021/nature-moves and https://osoc.be/editions/2021/bikeinfrastructure
When the first version of Buurtnatuur.be was online, Brussels Mobility sponsored an Open Summer of Code Project, resulting in the cyclofix theme. The codebase was refactored in order to support multiple themes just before the start of OSOC.
The first version of what would later become 'MapComplete' was financed by the Belgian Green Party. With the Corona-lockdown in full swing, they wanted to do something with nature and green spaces near people, maybe inventorizing all parks, forests and nature reserves.
The original website can still be visited, the oldest version still online.