I can give you some information on trolleybuses: among the cities you’ve listed, Vratsa seems to be the only place where you can still see ZiUs. They also have a few Ikarus trolleybuses which should be still in service. In Burgas the entire fleet was replaced with modern Skoda 26Tr vehicles. In Varna you can probably still see some Skoda 14Tr/15Tr, but they also acquired a batch of new 26Trs. Sofia retired many of its Ikarus 280Ts, but there still should be around 15-20 in service (mostly overhauled with a new front design). Here is an overview of the fleet situation in the remaining trolleybus systems:
Ruse – a full variety of second-hands from Western Europe plus maybe one or two Skoda 14Tr and ZiU
Sliven – looks like Skoda 14Tr remains to be their only model
Stara Zagora – they still might have two or three ZiUs in service, the other fleet includes a few Skoda 14Trs and low-floors: 26Tr & LAZ E183
Khaskovo –several Skoda 14Tr, and a couple of ZiUs
Pleven – used to be a kingdom of ZiUs, but they acquired 40 26Trs recently. Still, around 15 ZiUs should be in service.
Pazardzhik – currently the active fleet consists of eight LAZ-E183 low-floors, one modern ZiU, one Trolza-5275, and two Skoda 14Trs. All 9Trs seem to be retired.
Pernik –they had a couple of Romanian DAC-317E artics and around 10 ZiUs, but I’m not sure if their system is currently operating.
Systems in Plovdiv, Gabrovo, Veliko-Tyrnovo and Dobrich are definitely closed.