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:
Android: https://play.google.com/store/apps/details?id=com.thegrizzlylabs.geniusscan.free&hl=en
Iphone: https://apps.apple.com/us/app/genius-scan-pdf-scanner/id377672876
presentation timer this is my choice, colour code and simple in its
use
https://play.google.com/store/apps/details?id=com.chrisallenlane.presentationtimerpro
presentationtimer: up to three times very simple and straight forward:
https://play.google.com/store/apps/details?id=org.tmurakam.presentationtimer
presentationtimer several presentations with different times can be
programmed in advance and the bell can ring automatically:
https://play.google.com/store/apps/details?id=com.mikufu_works.presentationtimer
will be updated soon