Chum with white bread floating on top. White bread fly...hold on.
I've seen anglers use cotton balls, white fabric, etc, etc. Lots of realistic bread flies being sold. As for gar, the standard white frayed nylon rope on a hook works perfectly when fly fishing as well. Sight fish, cast near them and they will hit it. Their teeth get tangled in the rope. Works on spotted and longnose gar.