Let me introduce you to my 'second brain', it's called Evernote. Perhaps you already use it? If not, it's a simple, effective and easily searchable digital notebook. Whatever it is, from recipes to draft copywriting, it goes into Evernote first. 
And I'll let you into a secret, I'm actually writing this is Evernote now.
I work for Engaging Networks so admit that I have been completely spoiled for all things digital tools. I expect all the digital technology I work with to integrate nicely into my work and other tools I use, make my life easier and be fun to use! If it doesn't easily do what I need it to do, or can't be easily customised, then I'm afraid it just doesn't cut the mustard. That's why Evernote works so well for me. I can share notes, use their desktop and mobile apps across a number of devices and find what I need speedily. 
So in the spirit of sharing, I'd love to know your top tools! Here's mine:
1. Evernote - I've already expressed my love for this, but here's what they say "Capture, organize, and share notes from anywhere. Your best ideas are always with you and always in sync."  That sums it up nicely.
2. Pixlr Express - The simplest free online tool there is for cropping, resizing and very simple editing. They have a more serious editor, but I rarely use it. 9 times out of 10, the little jobs can all be done with Pixlr's Express web app.
3. WhatsApp for Desktop - OK so we all use WhatsApp on our phones, but the desktop version is a great asset to both your work and every day life. I use it for all sorts of cheats, such as speedily uploading phone images to my laptop. I wouldn't be without it.
So.... what's in your digital tool bag that you wouldn't be without?