I tried a lot of apps at some time, one important feature for me is that
all the tools work offline as well as online.
The best app i found is Locus (it has its own webpage here: http://www.locusmap.eu/)
either Locus Free : https://play.google.com/store/apps/details?id=menion.android.locus
or its pay version:
Locus Pro: https://play.google.com/store/apps/details?id=menion.android.locus.pro
both can use goolge maps and calculate tracks, can use vector maps and similar thing that can be downloaded before. One feature i like is that you can download goolge maps before a trip and store it. It has several "faces" for car or hiking, it can track your route or interface in special tracking tools like the one below. Really usefull are also the points of interest. They can be pu in groups and exported. I use to give them to friends so that they can enjoy a new city i already explored
There are plenty of sources for free maps i use:
http://download.mapsforge.org/maps/ for general vector maps used for car navigation and
http://www.openandromaps.org/downloads/europa for hiking and cycling
My tracks https://play.google.com/store/apps/details?id=com.google.android.maps.mytracks is a very usefull tracking tool with a lot of settings. it nicely interfaces with locus and after some tries is my choice nr. one.
Converter for images to pdf I recommend Genius Scan:
presentation timer this is my choice, colour code and simple in its
presentationtimer: up to three times very simple and straight forward:
presentationtimer several presentations with different times can be programmed in advance and the bell can ring automatically:
will be updated soon