I don't know your price range, but if you're looking for things on a shoestring budget or to get a few accessories to mix and match, you can find a ton of strappy chest things in unexpected places of amazon.
>The harnesses for pulling weight sleds
>This posture harness has cooler front detailing imo
>Another radio harness, you'd probably want to cut the straps shorter on this one
>Radio harness more on the edge of tacticool territory
>Looking for runner or crossfit gear can yield some more practical results
>A little more of a minimal pack if you don't mind the white with orange accents
>If you want to look like a cool techy sport dude, you could check shoulder harnesses
>More elastic/nylon chest strap harnesses
Anyway, hope this helps or at least inspires you to find some stuff that's more your speed in some unlikely places!