https://umap.osm.ch/en/map/open-table-tennis-switzerland_3307#9/47.0084/8.6682

We now have passed 3000 Table Tennis Tables in Switzerland alone. That is one seventh of the entire OSM TTT population. :-P

Tennis tables in Switzerland are often linked to schoolyards, public pools, campings, prisons a.s.o. Thus the main strategy is to download open datasets or OSM sets containing alike and then jumping from object to object in QGIS using the Go2nextFeature+ plugin and than screen the surroundings for Table Tennis Tables on the SwissImage. On detection you can directly jump to JOSM using the JOSM remote function of the Quick OSM plugin.