You will find reference(s) to the rivers listed below in The Rivers of Wales:

River Cadoxton
River Dee
River Dovey
River Ely
River Loughor/ Afon Llwchwr
River Monnow/Afon Mynwy
River Mule/Afon Miwl
River Nevern/Afon Nyfer
River Ogmore/Afon Ogwr
River Rhymney/Afon Rhymni
River Severn
River Usk
River Vyrnwy/Afon Efyrnwy
River Wye

Afon Aber
Afon Aeron
Afon Alaw
Afon Alun
Afon Alwen
Afon Alyn/River Alun
Afon Amman
Afon Braint
Afon Camlad
Afon Caradog
Afon Cefni
Afon Ceiriog
Afon Ceirw
Afon Cennen
Afon Clarach
Afon Cleddau
Afon Cletwr
Afon Clwyd
Afon Clywedog
Afon Colwyn
Afon Conwy
Afon Cothi
Afon Crafnant
Afon Crigyll
Afon Cwm-llan
Afon Cwmnantcol
Afon Cych
Afon Cyff
Afon Cynfal
Afon Cynon
Afon Ddu
Afon Dulas
Afon Dwyfor
Afon Dwyryd
Afon Dyfi/River Dovey
Afon Dyfrdwy/River Dee
Afon Ebbw
Afon Eden
Afon Edw
Afon Efyrnwy/River Vyrnwy
Afon Elái/River Ely
Afon Elan
Afon Elwy
Afon Ewenny
Afon Gain
Afon Gamallt
Afon Gann estuary
Afon Garw
Afon Glaslyn
Afon Goch
Afon Grwyne Fawr
Afon Gwaun
Afon Gwendraeth
Afon Gwendraeth Fach
Afon Gwy/River Wye
Afon Gwyrfai
Afon Hafren
Afon Hepste
Afon Hirnant
Afon Honddu
Afon Hore
Afon Irfon
Afon Ithon
Afon Iwrch
Afon Las
Afon Llafar
Afon Lledr
Afon Llugwy
Afon Llwchwr/River Loughor
Afon Llwyd
Afon Llynfi
Afon Loughor catchment
Afon Lugg/River Lugg
Afon Mawddach
Afon Melindwr
Afon Mellte
Afon Merddwr
Afon Miwl/River Mule
Afon Mynach
Afon Mynwy/River Monnow
Afon Nodwydd
Afon Nyfer/River Nevern
Afon Ogwr/River Ogmore
Afon Peddol
Afon Peithnant
Afon Pelenna
Afon Penrhos
Afon Prysor
Afon Pyrddin
Afon Rhaeadr-Fawr
Afon Rheidol
Afon Rheidol catchment
Afon Rhondda
Afon Rhyadr
Afon Rhydhir
Afon Rhymni/River Rhymney
Afon Sawdde
Afon Sirhowy
Afon Syfynwy
Afon Taf
Afon Taff
Afon Taff Bargoed
Afon Tanat
Afon Tawe
Afon Teifi
Afon Terrig
Afon Trannon
Afon Trothi
Afon Tryweryn
Afon Twrch
Afon Twymyn
Afon Tywi/River Towy
Afon Tywmyn
Afon Wen
Afon Wnion
Afon Wysg/River Usk
Afon Yr Ogof
Afon Ysgethin
Afon Ystwyth