Sidekix is a smart walking and urban discovery app which offers routes according to your interests.
TripScout produces high quality audio guides and offline maps with a quirky twist that I really appreciate - they cover the highlights you'll obviously want to know but also slightly more obscure points of interest. I don't get to travel as much as I'd like to anymore but have also found the guides to be fun armchair traveling - I can learn about cities I'd like to visit someday.
Instalist is a curated collection of beautiful, unique places to discover and immortalize, starting with 100 awesome photo spots. Explore, contribute, and make new friends by joining the community.
Kolu is a mobile app that matches travelers with their own local tour guide based on shared interests. When traveling to a new city, users can view profiles of local guides in that area who not only share their interests, but who are also close in age, speak the same language, and more. Kolu tours are always custom to the traveler's interests.