Slack is a great way to have instant messaging within your team and with clients. It can be accessed on both your desktop and your phone.
Evernote is a great tool to use for notetaking. Whether it's taking notes during a meeting or creating a to-do list, Evernote is easy to use and allows you to create tasks within your notes so you can mark them done as you complete them.
LastPass allows you to securely share and save your usernames and passwords in one location. This makes giving access to your email account to your Virtual Assistant easy, safe, and secure.