Why this is small on purpose
The big palette browsers hold millions of user-submitted palettes and have no quality floor at all. You cannot filter them by whether the colours are usable, because nobody ever measured them. Quantity was never the thing missing from this category.
So this library is hand-picked and small, and every badge on every card is computed at build time from the same engine that powers the tools. There are no save counts, because we would have to invent them.
What the filters mean
Body text safe means at least two colours clear 4.5:1 against white or black. One readable colour is a palette you cannot build an interface from.
Colour-vision safe means no pair collapses under any of the eight simulated deficiencies. This is a pairwise test, which is why a contrast checker cannot do it — it compares foreground to background and never foreground to foreground.
Chart safe is the strictest: every pair has to stay apart in full greyscale. A categorical palette that survives that survives everything, and it is what a chart series actually needs.