Fiocchi has just recently announced that they will be selling 12ga (3/4oz #8 shot) tracer shells designed for training & competition which use a cyalume (glowstick chemical) tracer component. It’s non-pyrophoric and thus gets around any anti-tracer rules anywhere. Here is a video:
The little cyalume canister is positioned ahead of the shot, and apparently if you hit a clay target with the canister directly, it will explode and light up the disintegrated clay dust with a glowing light in dusk conditions (cool). That was according to their website description, and you can see it happen in the video above at the 33 second mark. I guess little canisters of glowing cyalume get shot out to wherever you are aiming, but they claim it is non-toxic and biodegradable.