Off the top of my head:
Gmail or any email: Thunderbird is pretty sweet and I need to use it more, but mostly just use the web clients anyway.
If you own GoG games, you can use Heroic Launcher instead of GoG Galaxy. It’s gotten amazingly good, really fast. :)
Hey, points for Lutris! Thanks for sharing!
I’ve had issues in the past installing stuff with Lutris, although for advanced scenarios like using community engines and stuff, that’s really cool. I definitely have both installed on my machine for different reasons. Lutris handles EA / Origin stuff pretty well. (Titanfall 2 and Sims 2 Ultimate (not the Steam one) run beautifully on Linux, truly glorious!)
Electron annoys me as well, but I will say that I appreciate how Heroic hooks into GoG APIs. It handles auto-updates, cloud saving, play time logging, that kinda stuff that made Galaxy decent and had a degree of convenience-parity with Steam.
(Maybe Lutris does this too now?)
For a complete newbie , I’d say Heroic has a bit of a smoother and expected ramp to just “Download game and run.” But if you want more control, Lutris definitely has more options!
I also can’t recommend Bottles enough for other games that aren’t from distribution platforms. Shockingly simple.