Tools for cloud storage ([Tresorit](https://tresorit.com/)), email ([Protonmail](https://protonmail.com/)), instant-messaging ([Signal](https://signal.org/)), collaborative text documents ([CryptPad](https://cryptpad.fr/)), hard drive encryption ([VeraCrypt](https://veracrypt.fr/))

What I was able to find to replace Google Sheets:

- Google Sheets clones with a few additional collaborative features ([Zoho](https://www.zoho.eu/sheet/))

- ways to encrypt spreadsheets

- online databases ([Airtable](https://airtable.com/))

- ways to encrypt databases on servers ([Acra](https://github.com/cossacklabs/acra))

- kinda secure databases ([KoBo](http://kobotoolbox.org/) not actually encrypted but at least managed by UNHCR)