Search:
https://www.startpage.com (free)
Mail: https://www.posteo.de (12 EUR/yr)
Contacts: posteo does CardDAV (included)
Calendar: posteo does CalDAV (included)
Chat: Signal (though not decentralised, the only service that seems robust, trustworthy and usable by the not-so-technical (=friends)); (free)
Drive: Dropbox w/ partly encrypted content (currently GPG, but should move to cryptomator or similar for convenience/scaling; Spideroak is not open-source despite promising to become that for years now, don't see why to trust them); (free plan)
Youtube: :( - impossible to replace, i guess
Maps: https://www.openstreetmap.org on occasion, mostly still G. Maps :(
also:
Desktop OS: Ubuntu (I don't see significant privacy concerns currently; also, this is the only OS i would recommend to either browse-and-mail users or interested and motivated friends)
Mobile: Still on OEM-Android; would switch to CyanogenMod if i could root safely, see below (in future: CopperheadOS); using it with most G. Apps disabled, NetGuard blocks all but G. Services (required for Play & Signal)
Browser: Firefox w/ uBlock, NoScript, Request Policy, HTTPS Everywhere, Decentraleyes (hasn't been mentioned here?!), Random Agend Spoofer (disable in reverse order if this seems excessive/redundant)
looking for:
Skype: good SIP client and especially server - anyone? :) (also non-SIP alternatives...)
Mobile hw: good hardware (Nexus seems paradoxically logical to either get serious updates or compatibility to projects like Copperhead/Cyanogen; maybe also S. Galaxy?)
Mobile sw: open-source scripts to root above "good hardware"; open-source su apps (phhusson's seems to be the only one outside CyanogenMod? and still in rough beta)