Depends on the kind of concentration. If I'm programming or doing some kind of math, I want fury. I'm reaching for Slayer or Megadeth or the Doom sound track. Nothing like Angel of Death to plow through something.
If it's more contemplative, power ballads. Something I can sing without focusing on it. I Want to Know What Love Is. Keeps pace, but it's more emotional. Keeps me in that thoughtful place.
Cooking, woodworking, cleaning. Something active but not on the whole fast. Heavy metal, southern rock, or blues. Kiss, CCR, Lynyrd Skynyrd, BB King. Something even tempo that can pick up and come back down. Freebird followed by Fortunate Son is a good example.
Either ambient instrumental music (lots of Brian Eno) or any music that I know all the words to (so that my brain doesn't have to actively process the lyrics).
When I really need to concentrate I put on music in a foreign language. Mainly German because I've found a lot of German bands I like. Some of my favorites that sing mainly in German:
Years ago I got a disc called Sounds of Slashdot. It was at a con, I think.
Anyway it's got some "gamemaster" "lost tribe" thing among some musical tracks on the CD. I have No Idea what it is, but I put it on and the sounds fucks with distractions and I can enter the Flow more easily for work. It's a great trigger.
Anything without vocals so that it doesn't force me to actually think about it, just vibe.
Lately Chikoi The Maid (maidcore rock) or Gnome (the Father Of Time album, just-riffs-rock?) to some dnb/techno stuff, depends on the mood and how hard I need to focus - faster is better then.
Emancipator fucks heavy. I don't think I've ever heard an artist capture the feeling of misty forests and snow so perfectly. Just nature really. Safe in the Steep Cliffs and Dusk to Dawn are so evocative.
Hell yeah! I learned of them when my partner and I were walking around at a festival, and we passed a stage with the most relaxing music… we just immediately sat down, then laid down in the grass and vibed for a good half hour. Sooooo good.
Honestly, I cant listen to anything while trying to concentrate. Music distracts me when I'm trying to focus on a mental task. Now if I'm doing physical labor or whatever, much easier. 80s music for sure. New Wave, synthpop. Good stuff.