Business Calendar 2
https://play.google.com/store/apps/details?id=com.appgenix.bizcal

Evernote
https://play.google.com/store/apps/details?id=com.evernote

Todoist
https://play.google.com/store/apps/details?id=com.todoist

Wunderlist
https://play.google.com/store/apps/details?id=com.wunderkinder.wunderlistandroid

Google Keep
https://play.google.com/store/apps/details?id=com.google.android.keep

Cal by Any.do
https://play.google.com/store/apps/details?id=com.anydo.cal

Sunrise Calendar
https://play.google.com/store/apps/details?id=am.sunrise.android.calendar

UpTo - Calendar and Widget
https://play.google.com/store/apps/details?id=com.upto.android

ClaenMob
https://play.google.com/store/apps/details?id=com.appxy.calenmobfree

WAVE Personal Calendar
https://play.google.com/store/apps/details?id=com.esites.ecal

Today Calendar
https://play.google.com/store/apps/details?id=com.underwood.calendar_beta

Tasks Free
https://play.google.com/store/apps/details?id=ch.teamtasks.tasks