Here's my GTD Stack


My stack has evolved over the years and I've probably used all of the apps you can find on the app store along with paper and here's where I'm at now:

Drafts IOS app (to just capture the initial idea quickly. I've found it loads faster than Evernote. I can export the note into Reminders)
Apple default Reminders app which feeds several other apps
Apple default calendar (I need it to sync to iCloud to sync to my laptop and also power below 2 calendar apps)
Calendars 5 (ironically not for the calendar but for the task list which can be separated/organized very easily into different roles/someday maybe/etc)
Fantastical Calendar (just like the layout)
blank notebooks/pieces of paper (for freestyling notes), then take a picture of it into Evernote
Evernote (for someday/maybe later notes and pictures of handwritten notes.)

Recently added apps for Eisenhower Matrix:
Priority Matrix (web app, iPhone and desktop - still testing it out)
Microsoft To Do app (to sync with Microsoft Exchange in order to send tasks from Apple Reminders to Priority Matrix which only works with Microsoft Outlook, To Do and Jira)

Okay, done procrastinating in 4th quadrant, time to get back to High priority 50k feet tasks!