Coins from Odrysian Kingdom
The Odrysian Kingdom was a state union of over 40 Thracian tribes and 22 kingdoms that existed between the 5th century BC and the 1st century AD. It consisted mainly of present-day Bulgaria, spreading to parts of Southeastern Romania (Northern Dobruja), parts of Northern Greece and parts of modern-day European Turkey.

The Odrysian kingdom had maintained continuity with its own kings, but broken up into several kingdoms (including Canite and Odrissae) by the early second century BC, until succumbing to complete Roman conquest in 146 BC. In 100 BC a Thracian kingdom was restored, possibly by a son of Beithys, one of the last kings of the Odrissae, it is not clear if it was a vassal of Rome or entirely independent. The Odrysian king was murdered by his wife and his kingdom was completely subjected to Rome in 46 AD.
Odrysian Kingdom
(1) Odrysian Kingdom | Parion imitative
An AR Hemidrachm struck 500-350 BC in Thrace
Obverse: head of Medusa (Gorgoneion) facing

Reverse: incuse square with cross and pellet

Diameter: 13 mm
Die Orientation: -
Weight: 1.71 g
Forum note: "This type has traditionally been attributed to Parion, Mysia or as a Celtic imitative of the Parion type. Based on find locations in the area of Plovdiv, Haskova, Stara Zagora and Yambol in Bulgaria, Topalov has reattributed this imitative type to the Thracian Odrysian Kingdom. He notes they may have been struck by a tribal mint or by one of the Greek cities within Odrysian territory to pay their annual tax to the tribe."
cf.SNG France 1347; cf.SNG Copenhagen 256
(2) Rhoemetalces III | Caligula
An AE unit struck 38-41 AD in Thrace
Obverse: Diademed draped bust of Rhoemetalces III left; BAΣIΛEYΣ_POIMHTAΛKAΣ

Reverse: Laureate head of Caligula left; ΓAIΩ KAIΣAP_I ΣEBAΣΤΩ

Diameter: 24.5 mm
Die Orientation: -
Weight: 10.77 g
Kingdom of Thrace
Caligula RPC 1723; BMC 2; Jurukova 209; SGI 5407; Moushmov 5805
(3) Rhoemetalces I | Augustus
An AE unit struck 11 BC - 12 AD in Thrace
Obverse: Diademed head of Rhoemetlalces I right; BAΣIΛEΩΣ__POIMHTAΛK_OY

Reverse: Bare head of Octavian Augustus right; KAIΣAPOΣ__ΣEBAΣTOY

Diameter: 18.5 mm
Die Orientation: -
Weight: 4.1 g
ex Roma Numismatics
RPC I 1718; Youroukova 194; BMC Thrace p. 209, 7; SNG Cop 1192; SNG Tub 974; SNG Evelpidis 1124