CatOfEvilGenius posted these separated track outfits, but the only part of that upload for teens was a DR for the Maxis tracksuits with a different bodyshape; there were no separates for TF. If someone made an outfit with a track-type jacket top and jeans/sneakers bottom, that would be cool too, but it seems a bit specific: track separates would be more useful for the general simming populace. It's unclear why Cat didn't think that would be a thing teens could use. If it IS actually available for teens, then I apologize, but the download did specify Adult/YA.

Striped sleeves a la Adidas would be nice, as would the red color worn by Sadie Sink in the screenshot (or dark green, or any color actually; I can't afford to be picky.)

The second item is a headband accessory, in green camo. Someone made one for Sims 4, as seen in the second shot. Not sure where it came from: I couldn't find it on MTS, the shot is from Pinterest.

Maybe these? (not 100% sure they're custom, but I think the last set of files are)
https://rudhira.tumblr.com/post/656...sweats-replaced

Or these? (slightly different texture, using Rudhira's meshes)
https://andrevasims.tumblr.com/post...ksuit-separates

Possibly pants (only) here, though LJ isn't working properly for me now, so can't see the full post:
https://puremorphin.livejournal.com/2917.html

These are fullbody conversions of the YA tracksuits, which have a slight Adidas-look. Maybe that works?
https://modthesims.info/download.php?t=301127

There's a red (fullbody) recolor here, maybe that could work?
https://modthesims.info/d/267333/fi...letic-wear.html

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For the headband, are you looking for that particular one as a 4t2 conversion, or a(ny) similar headband?
(Original is here, in case that helps anyone: https://theafricansim.tumblr.com/po...ick-little-mesh)

No idea if that one has been converted, but there are some bandanas/headbands around:

Hairs:
http://www.insimenator.org/index.php?topic=7476.0
https://www.thesimsresource.com/dow...-set/id/205957/
https://www.thesimsresource.com/dow...-set/id/206004/

Accessory:
https://sims-life-in-brunei.blogspo...for-sims-2.html

Yeah, that one showed up on Pinterest and looked like a good size & shape, tied neatly in the back, plus it was an accessory, and came in camo. Basically exactly what I was looking for, if it were 4t2. They're nicely done.

As for the tracksuit jackets, the only reason I checked out the Cat upload was it looked like it was going to be separates for both adults and teens, that could be worn with jeans. What the hey, I'll try the ones you linked and see what works. Thanks!

I just ran into these bandana-hairdos by Artemida , which are a great shape also... if the bandana part were an accessory, I'd grab the green one as "close enough" to an army-camo look. The Sim I see wearing it has very short hair.