Recruitment agencies, although free, won't get you much other than what you can find yourself. Delivery food services are always hiring and they're international friendly. Thuisbezorgd is the most popular one around here. Stores/ restos are also an option.
If you like babysitting, you can apply for Näpp, which is a babysitting platform for internationals. Also, quite many restaurants in the city center have internationals working. I know that the Rum Club is looking for new staff!