I use:
RateYourMusic to keep track of albums ive listened to
Last FM for finding similar songs and albums
Deathgrindclub to see new releases although i dont use it very often
Reddit for basically everything finding new music, discussing it, ect...

No Clean Singing hosts a fantastic regularly updated list of shows going on in the Pacific Northwest area that I've grown to rely on since moving up here from the Mojave desert.

https://www.nocleansinging.com/nw-metal-calendar/

Apart from MA I only really use RateYourMusic (you can add me @ Bonejammer if you want!), but that site I do use extensively for keeping track of what I'm listening to and what I want to check out or listen to some more.

I'm a moderator on HMR so that's my main go-to. I also use RateYourMusic and Discogs.

I really only use this and Angry Metal Guy.

Reddit is a hellhole I will never go back to.

Facebook and Instagram are still the primary way of finding out about upcoming live concerts here. On FB I use the Feeds -> All option, which basically just shows you posts from bands/pages and friends you actually follow, as opposed to a shitpile of suggested posts. Network with enough people in the scene, and whenever something cool's announced it's there in the feed, even just because a bunch of friends mark it as 'Interested'. The catch is that the feed's in reverse chronological order and you have to scroll through the day's posts back to where you were last up to if you want to ensure you didn't miss anything. There's a wider variety of ticketing websites in use here now so it's not so easy to look through those to find out what's upcoming.

Last.fm for my music listening history. RateYourMusic for rating albums (something I never imagined I'd do until a few years ago) and the occasional discovery. Discogs and occasionally MusicBrainz for looking up info, eg. to pick the more common spelling of a song title for scrobbling to Last.fm. HMR and UM forums. Bandcamp or occasionally 7Digital for buying downloads. YouTube is one of my preferred sites for previewing music - you can click through different songs quite fast, as opposed to Spotify's unresponsiveness on my PC.

I actually use my own website to document all the bands I've seen live and the venues/dates I saw them. Eventually other people will be able to use this, but I need to do a lot more programming for it to work.

Setlist.fm to look for different metal bamd setlists.

Forgotten scroll. A greek forum dedicated to metal.

Spirit of metal. Similar to Encyclopedia Metallum. Created by some french metal fans.

Christian Metal Realm. Forum for christian metal music and other stuff.

That's a great idea! I use https://www.concertarchives.org/ to keep track of some of those details from over the years.

Apart from MA, I am often on Sonic Perspectives since I work for them, and lately I've been perusing Bravewords and Metal Injection because some of my writing has been featured on those sites, though it's more an occasional thing. As for documenting my own listening habits and concerts I've attended, I sometimes do that on my personal Instagram page (I have a separate one for my band), but lately most of my concert attendance is documented on Sonic Perspectives, including an awesome show just a couple weeks ago featuring Immortal Guardian and Firewind.