There are several apps that can help you navigate in the cities and the countryside. Below are a few which we recommend based on our experience.
Maps.me / OSMand - For offline maps, hikes, off-road, villages. Maps of the region can be downloaded in advance and you can do simple route planning. Not very suitable to plan a longer route, though it will sometimes suggest interesting ‘detours’. Don’t rely on this app entirely, especially on its time estimates.
Yandex Navi - For navigating in the major cities, planning longer trips. Great for time estimates and finding more functional routes, but will lead you down strange tacks every now and then. iOS - Android
Google Maps - When you’re not in the car, Google Maps is your best friend. It has the most listings of locations, business, and so on. It’s also functional for route-planning of longer trips and the time indications are pretty accurate usually.