Most of my planning is done with on-line resources before I depart, although I do use some apps. Here's a rough list of my prep materials.
SkyVector: Free on-line site. Provides official sectionals I think for all the US. Also provides "DROTAMS", which they define as Drone NOTAMS. I can't live without this.
FAA NOTAM search site:
PilotWeb: Home
METARs:
METAR Reader | Free online METAR services Gives the actual METAR report, then translates it into plain English. Just plug in your local ICAO code.
For air traffic monitoring, I use a handheld Uniden BC75XLT scanner set to local tower frequency, if needed.
Insurance: Verifly. Pay by the hour with an iPhone/Android app.
Apps: Hover - provides weather, but not METARs, includes map with restricted areas shown, no NOTAMs. The log feature of Hover is pretty good, and fills in some of the data automatically, like time, weather and GPS coordinates, but I would like to see a few additional items there for commercial use. B4UFly - the FAA app, I use just to double check I'm not in a restricted fly area. But it's not always reliable, as it will show every little touchdown point for an aircraft, like hospitals, and depict them as restricted airport airspace. (The FAA admitted their app had some issues.) And I'm not sure which app is correct, but the B4UFly app says I cannot fly at my house because I am in airport restricted airspace, but the Hover app says it's OK to fly because I am outside the airport restricted airspace. I live almost exactly five miles from a major international airport, so I understand the confusion, but one of these apps is giving me bad advice. I won't suggest any NOTAM or METAR apps because there seem to be a million of them out there for actual pilots.
Is that the kind of info you're looking for? The biggest issue for me is restricted airspace. It's everywhere around my location, so I really have to be careful.
Max