The Basetrip - Cities - Travel information for 650+ cities & 230+ countries
Sygic Travel Maps - Itinerary planner for independent travelers
EntryAdvise.com - With EntryAdvise, you can check COVID restrictions, the entry requirements and useful travel info for all countries. It makes a good resource for frequent-travelers and backpackers.
Detour - Immersive audio walks, now in 17 cities
Lonely Planet - travel guide book publisher
Foursquare 10 - Your ultimate city guide, in your pocket