abductor pollicis longus,the extensor pollicis longus,and the extensor pollicis brevis

Flexor pollicis longus.

There are many muscles in the hand. Here are a few:

extensor carpi radialis brevis

extensor carpi radialis longus

extensor carpi ulnaris

extensor digitorum communis

extensor indicis proprius

extensor digiti minimi

abductor pollicis longus

extensor pollicis brevis

extensor pollicis longus

flexor carpi ulnaris

flexor digitorum profundus

flexor digitorum superficialis

flexor carpi radialis

flexor carpi ulnaris

palmaris longus

flexor pollicis longus

abductor pollicis brevis

flexor pollicis brevis

opponens pollicis

adductor pollicis

palmaris brevis

abductor digiti minimi

flexor digiti minimi

opponens digiti minimi

Then each finger has a set of lumbrical muscles

and 3 volar and 4 dorsal muscles

Median Nerve ( starts at C6) Flexor Carpi Radialis, Palmaris Longus Ulnar Nerve ( starts at C7) Flexor Carpi Ulnaris, Flexor Digitorum Profundus Median Nerve ( starts at C7) Flexor Digitorum Superficialis, Flexor Digitorum Profundus Radial Nerve ( starts at C6) Extensor Carpi Radialis Longus, Extensor Carpi Radialis Brevis, Extensor Carpi Ulnaris, Extensor Digitorum Communis, Abductor Pollicis Longus, Extensor Pollicis Longus, Extensor Pollicis Brevis Median Nerve ( starts at C8) Flexor Pollicis Longus, Abductor Pollicis Brevis, Flexor Pollicis Brevis, Opponens Pollicis, Lumbricals Ulnar Nerve ( starts at C8) Adductor Pollicis, Abductor Digiti Minimi, Flexor Digiti Minimi, Opponens Digiti Minimi, Lumbricals, Dorsal interossei, Palmar interossei

Abductor Pollicis Brevis, Flexor Pollicis Brevis, Opponens Pollicis, Abductor Digiti Minimi, Flexor Digiti Minimi, Opponens Digiti Minimi, Adductor Pollicis, Lumbricals, Palmar Interossei, Dorsal Interossei, Abductor Pollicis Longus, Extensor Pollicis Brevis, Extensor Pollicis Longus, Extensor Indicis, Flexor Digitorum Superficialis, Flexor Digitorum Profundus, Palmaris Longus

The muscles that flex your fingers are located on the anterior side of the forearm and hand. The muscles that extend your fingers are located on the posterior side of the forearm and hand.