The Hemidrachm denomination - Variants: Triobol
The Hemidrachm was an ancient Greek coin denomination with a value of 3 obols, which is half a drachm. it is also often called a triobol.

The hemidrachm generally weighs around 2.15 grams when struck in silver, but was also struck in bronze.
Hemidrachm|Triobol

(1) Achaean League c. 86 BC
Obverse: head of laureate Zeus right
Reverse: fish under (AX) monogram all within wreath; (APT) left / ΔY up
Ref: Clerk 55; BCD Peloponnesos 482
(2) Achaean League 160-146 BC
Obverse: laureate head of Zeus right
Reverse: (AX) monogram, thunderbolt below, all within wreath; ΞB / K_A / M
Ref: Benner 17; BCD Peloponnesos 1551.1;...
(3) Achaean League c. 188-180 BC
Obverse: laureate head of Zeus right
Reverse: (AX) monogram within wreath; A_N / CΩ
Ref: Benner 5; BCD Peloponnesos 1492.2; ...
(4) Achaean League c. 175-168 BC
Obverse: laureate head of Zeus Amarios right
Reverse: lyre above (AX) monogram, all within wreath; ΔΩ_PO
Ref: BCD Peloponessos 27.1; McClean 6431...
(5) Achaean League 100-80 BC
Obverse: laureate head of Zeus right
Reverse: (AX) monogram, trident below, all within wreath; A / Π_Λ / (YE)
Ref: BCD Peloponnesos 1593.2; Benner 4; ...
(6) Apollonia Pontica c. 350-300 BC
Obverse: facing head of Medusa
Reverse: anchor flukes up; A / crayfish
Ref: Apollonia p. 347, 1; SNG BM Black S...
(7) Argos 125-80 BC
Obverse: forepart of dog
Reverse: big A, trident below; Δ _ A / MAP
Ref: BCD Peloponnesos 1145; SNG Copenhag...
(8) Byzantion 387-340 BC
Obverse: forepart of cow left, below dolphin swimming left; (BY)
Reverse: wide ornamented trident
Ref: Schönert-Geiss Byzantion 778; SNG B...
(9) Cherronesos 386 - 338 BC
Obverse: Forepart of lion right, head reverted
Reverse: Quadripartite incuse square with alternating raised and sunken quarters; pellet in one sunken quarter, wreath in the opposite
Ref: McClean 4076-7; HGC 3, 1437
(10) Cherronesos (Thrace) 400-350 BC
Obverse: forepart of lion right, head turned back
Reverse: quatripartite incuse square, grain ear in one section, X· in other
Ref: McClean 4103 var (dot over E)
(11) Hadrian 120-121 AD
Obverse: Laureate bust left draped shoulder; AVTO KAIC TPAI AΔPIANOC CEBACT
Reverse: Nike walking right holding wreath and palm branch; ETΔ
Ref: Metcalf 86a; Sydenham Caesarea 255;...
(12) Hadrian 120-121 AD
Obverse: AVTO KAIC TPAI AΔPIANOC CEBACT, laureate draped bust right
Reverse: ET Δ, Nike walking right with wreath and palm
Ref: RIC 351, RSC 282, MIR 522v, King 39
(13) Kroton c. 430-420 BC
Obverse: Pegasos left; Ϙ
Reverse: Tripod with 3 ring handles and legs ending in lion’s paws; ϘPO
Ref: HN Italy 2127, SNG Cop 1788
(14) Lokri Opuntii c. 340-330 BC
Obverse: Head of Persephone right wearing wreath of grain, single-pendant earring, and pearl necklace
Reverse: Ajax the Lesser (son of Oileus) nude but for crested Corinthian helmet advancing right in fighting attitude holding short sword and shield on left arm ornamented inside with coiled snake (control symbol), helmet crest below; OΠONTIΩN
Ref: SNG Cop.51, de Nanteuil 886, BCD Lo...
(15) Neapolis (Macedonia) c. 424-350 BC
Obverse: facing head of Medusa (Gorgoneion), tongue protruding
Reverse: diademed female head right; NEOΠ
Ref: SNG ANS 430-454; SNG Cop 227; SNG B...
(16) Nero AD 58-60
Obverse: NERO CLAVD DIVI CLAVD F CAESAR AVG GERMANI, laureate head right
Reverse: Victory seated right on globe, holding wreath
Ref: RPC 3645; RIC 617; Sear 1949
(17) Odrysian Kingdom Odrysian Kingdom | Parion imitative 500-350 BC
Obverse: head of Medusa (Gorgoneion) facing
Reverse: incuse square with cross and pellet
Ref: cf.SNG France 1347; cf.SNG Copenhag...
(18) Olympia 312-271 BC
Obverse: laureate head of Zeus right
Reverse: eagle right; olive leaf right; F _ A
Ref: BMC 84. Dewing 1896. McClean 6637. ...
(19) Parion c. 350-300 BC
Obverse: head of Medusa facing (Gorgoneion)
Reverse: bull standing left, head turned right; dolphin above; Π_A / PI
Ref: BMC 22
(20) Pharsalos c. 450-400 BC
Obverse: helmeted head of Athena right
Reverse: head of horse right; Φ A / P Σ
Ref: Lavva 75 (V38/R44)
(21) Phasis? c. 425-325 BC
Obverse: Archaic female head (Artemis Dali) right
Reverse: Head of bull right
Ref: SNG BM 1013-1018; Hind 7; HGC 7, 21...
(22) Phokian Confederation c. 440-420 BC
Obverse: facing bull head
Reverse: head of Artemis right; Φ O K I
Ref: SNG Cop 99 ff.
(23) Ptolemy III 246-222 BC
Obverse: Diademed and horned head of Zeus-Ammon right
Reverse: ΠΤΟΛΕΜΑΙΟΥ ΒΑΣΙΛΕΩΣ, eagle standing left on thunderbolt, wings closed; XP monogram between legs, filleted cornucopiae in left field
Ref: CPE B396; Svoronos 965; SNG Copenha...
(24) Ptolemy IV 221-204 BC
Obverse: Diademed head of Zeus-Ammon right
Reverse: Eagle standing left on thunderbolt; cornucopia to the left; ΠTOΛEMAIOY_ΒAΣIΛEΩΣ, ΔI
Ref: Svoronos 1127; SNG Cop 202; Noeske ...
(25) Ptolemy IV 222-205/4 BC
Obverse: Head of Zevs Ammon
Reverse: Eagle on thunderbolt
Ref: Svoronos 1128; Weiser 52
(26) Rhodos 170-150 BC
Obverse: Radiate head of Helios facing slightly right
Reverse: APTEMΩN / P-O, rose with bud to right, hook to left; all within incuse square.
Ref: Jenkins 50; SNG Helsinki 658. VF
(27) Sikyon c. 330-280 BC
Obverse: Chimera walking left; ΣI
Reverse: dove flying left, •
Ref: BCD Peloponnesos 292; SNG Cop 64; B...
(28) Sikyon
Obverse: Dove flying left
Reverse: M Monogram
Ref: SNG Copenhagen 103
(29) Tanagra 457-448 BC
Obverse: Boeotian shield
Reverse: forepart of horse right within incuse square; T_A
Ref: Dewing 1498 (same rev. die)
(30) Teos c. 500-460 BC
Obverse: Griffin seated right
Reverse: rough incuse square
Ref: Balcer group XXI, 51-6; SNG Copenha...
(31) Thebes 426-395 BC
Obverse: Boeotian shield
Reverse: Kantharos; club above; Θ_EB
Ref: BMC 64; SNG Cop. 289
(32) Trajan 100 AD
Obverse: Laureate head of right; AYT KAIΣ NEP TPAIAN ΣEB ΓEPM
Reverse: Head of Zeus-Ammon right; ΔHMAPX·EΞ·YΠAT·Γ
Ref: BMC 57-58. Sydenham 176
(33) Trikka c. 480-400 BC
Obverse: naked Thessalian youth standing right, restraining forepart of unruly bull prancing right
Reverse: forepart of bridled horse prancing right, within incuse square TPI_KK_AI (retrograde)
Ref: SNG Oxford 3933; BCD Thessaly II 76...