I find it fascinating how the presence of such a low threshold to win any seats in the Netherlands keeps leading to the proliferation of these teeny-weeny parties that have only the most microscopic differences from other parties. I mean seriously - why do you need a Party for the Animals AND a Green party? Why have D66 and Volt and PvdA etc... in any other country these parties would be factions within larger parties.
Not saying its necessarily good or bad - it just "is"
I would think of the difference between PvdA and D66 as being roughly analogous to that between Labour and the Lib Dems, and the latter just about manage to remain relevant in the majoritarian UK. But Volt are a different matter: they are supposedly a pan-European party, but in most European countries they are essentially irrelevant in terms of actually winning seats, while in the Netherlands they have managed to find a niche.
Then there's the mass of virtually indistinguishable tedious populist right parties. And, perhaps more interestingly, the parties which have quite a clear niche but one which wouldn't be big enough to win seats in most electoral systems: PvdD, DENK, 50Plus (though they seem to be on the way out), and to some extent the SGP (though perhaps the concentration of support they have in some areas would win them seats under other systems too).