Q.What Shrubs Can I Plant In Bulgaria
I have recently moved to Bulgaria and would like to plant some shrubs in Bulgaria temperatures in the Summer can reach 90+ and in the winter 40 below. These temperatures are extreme. Rainfall is intermittent but when it rains it downpours and can cause flooding.

Certified GKH Gardening Expert
According to my research, your area is most equivalent to our zone 7 at its coldest. We have multiple articles that will help suggest plants for the climate:
https://www.gardeningknowhow.com/garden-how-to/gardening-by-zone/zone-7