P-344-345D  Views from Romania / Tourism
This seems to be an inexhaustable source of different images, 39 so far here.... (so prepare to scroll down..) 4 different c-marks

I. c194  Stamp w printed perforation (type 4)

State Circus, new building	Timil de Sus	Pioneer artists
Bucharest - Floreasca blocks	The pre-school of friends of enterprise??	Bucharest "Stalin Park"
Bucharest  23 August Stadium	Bucharest - 23 August Icerink	Bucharest - New constructions
Bucharest - Pioneer palace

c580 No perf (type 2)  At least I found one of these...

Dobrogea - ruins

c585 no perf (type 2)

Busteni	Iasi - Cultural Palace	Iasi - National theatre
Bucharest Palace Hall  (later philatelic cancel)	Bucharest Palace Hall Square (later philatelic cancel)	BUCHAREST - Opera
Sibiu   (later philatelic cancel)	Sighisoara	Sovata
Mangalia	Mangalia	Oradea
Cluj - General view	Hunedoara . General view	Braila - Piata Lenin
Mamaia	Mamaia	Mamaia - New constructions
Ocna-Sibiulul	Paltinis

c980 No perf (type2)   (c980 is also mark for P357 Winter Tourism - very hard to say which is which...  c980 w snow in motive I place as P357)

Cluj	Oradea	Oradea
Timisoara	Galati	Onesti
Iasi	Iasi	Piatra Neamt