To-do lists
I use 2 simple text documents that I keep open with vim on my first workspace.
One of the document is arranged into multiple sections such as:
Learning - Projects - Daily - Goals - Notes
The second one is my schedule and mini things that needs to be done fast.

Contacts

I keep my contact list in hnb

Calendar

I just do:
Then I know the day and I can manage stuff with my schedule.

Note taking and storage

I also take notes with hnb

Email setups
On my phone I use gmail (Android). It's pretty well made and has a slick interface.
On my laptop I use sylpheed.

Device synchronization

I backup things with rsync and I also sync my vps using rsync.

For the rest I tend to use any mean of storage. I put files on my phones, transfer them to my laptop. Send messages to myself on telegram with files I need. Upload them to ioup (pastebin) service. etc..