For mobile mail client apps there's K9 and Fairmail, being K9 fairly used.
For calendar, besides mentioning davdroid you should also mention icsdroid both work together.
As phone OS, Something in between LineageOS and /e/, is LineageOS for microG. LineageOS for microG is in essence Lineage with necessary changes to provide microG and all of its functionality. Actually the /e/ is in essence Lineage for microG changing and adding default apps as well as its look and feel.
For mail service, calendar service, contacts service, and if you'd like also for Gogle Drive replacement, I'd also mention /e/ and nextCloud, since Nextcloud is an open source self hosted cloud providing all those services and more, and there are 3rd parties offering Nextcloud service such as /e/, thus providing those services.
You don't mention camera, but Open Camera is a good mobile app to keep in mind.
Related to mail clients, and for encryption purposes, I would also mention OpenKeychain.
Finally I don't know if popcorntime deserves being mentioned on TV and similar, since Kodi is also mentioned there... Though not sure if it would imply mentioning some VPN services as well (you do mention you use PIA though).