All the websites below are using WPSOLR, and contain tens of thousands of posts or products
Classified ads – Search in 500,000 ads – http://loot.com/
Office supplies -Search in 15,000 products – https://www.violetofficesupplies.co.uk/
Retail -Search in 120,000 products – https://www.brandcity.dk/
Price comparator -Search in 30,000 products – https://www.healthnutcompare.com/
Art -Search in 100,000 products – https://www.oceansbridge.com/
Photos marketplace -Search in 20,000 products – https://www.diversityphotos.com/
Music shop -Search in 50,000 products – https://www.koormuziekshop.nl/
Job listing -Search in 100,000 Jobs – https://www.qym.review/
City Events -Search in 80,000 Events – https://www.tip-berlin.de/
Newspaper, multi-lingual – http://www.avenir-suisse.ch/