Are there tile sets you definitely think are useless that should be removed?
There's the ones that are just artsy renderings of other maps we have. They don't add anything really and the maps aren't particularly useable
- Thunderforest Pioneer
- Thunderforest Spinal Map (its pretty unreadable too with black-on-dark grey)
- Stamer Toner (though the hybrid version on leaflet is a big improvement as the lines for roads have Mapnik underneath it providing more context)
- Stamer Watercolor
- ESRI World Gray Canvas
Are there ones you like and use a lot that would be annoying to you to have removed?
Mapnik, German OSM (though if that was replaced by French OSM, I wouldn't mind as it does the same thing, just with a different appearance and a different default language), ESRI World Imagery.
Are there ones on the leaflet-providers demo page that we don't currently have that you'd like to see added? Note that not all are available for free, so your favorite might not be possible.
OSM.France - OK, it's benefits are similar to OSM.DE, namely the transliteration of non-Latin characters where possible and the showing of proposed routes. Arguably it's not as good as the German version (less transliterations available), but I'm still bitter that Mapnik changed from that cartography and it was very nice to see that colour scheme again!
If free, then GeoportailFrance / GeoportailFrance.ignMaps would be great. Similarly there's USGS layers.