The Holland America Line tokens would be interesting to find but it will be difficult to sort them from the modern casino issues when seen in advertising. The three tokens can be seen
here along with some misinformation about their purpose.
The Van Ommeren tokens appear to be a little different,
Catawiki has this information: (Translated from the Dutch)
Not because of the currency reform after the Second World War, but because of the planned automation of the bar in the evenings, the firm Ommeren in 1964 and 1968, coins made of 10 cents, 25 cents, 1
euro gulden and 2.5 guilders. Van Ommeren has surrendered the remaining medals around 1975 by the Royal Mint.
They show just this one type.