These Badges of the Union Of Artists Of Bulgaria do not give away much information by themselves. It is unknown if the Badges are for different types of activity or different classes of the same award.
The "not round" example is certainly dual colour as it hasn't seen too much action. The gold has remained gold but the silver has tarnished quite a bit on the front.
If these Badges were valued a bit more and retained their documents we would probably have a better idea of just what most of these meant. It's difficult when the recipient, their heirs, the dealers and more often than not, the collectors don't care about the Badges let alone the paperwork that came with the Badges.
Most of the Bulgarian Badges I've collected have come in "job lot" boxes full of mixed awards with Communist Orders, Medals and Badges selling for on average 20-25 cents each within the lots.
It is amazing how much information can be dug up with a small amount of research which completely illuminates them.