I'm obviously not Bulgarian (but sooner or later I'll speak their language ), but since I know cyrillic, I can help That would be Signal- Da Te Zhaduvam Az
And yeah, these songs are amazing, indeed!
Yes, that's the spelling in latin and "da te zhaduvam" here means to desire you strongly, it's not literally because "zhaden" means thirsty, so it's figurative expression
So if you liked Signal, here is next their song "Сбогом/Farewell " (Sbogom), which in this chart is under number 24 of all greatest BG songs and is their second best positioned song in the list after the previous one which was №6 :