Kadaster.club
I built https://kadaster.club, which shows all land parcel data of the Netherlands. There's some existing sites for this but they quickly try to upsell you stuff and/or are slow and don't show the parcel data when zoomed out too much. None of the other ones I've seen render the parcel data as vectors either, which hurts my eyes. I also just added https://kadaster.club/mcp so an agent can query the same data and even look in the data available on https://omgevingswet.overheid.nl/ to answer question around what is allowed and what permits you need for a specific location