This page explains a brief introduction to the substrate in Saami languages, already present in the proto-Saamic period: https://en.wikipedia.org/wiki/Pre-Finno-Ugric_substrate#:~:text=Pre%2DFinno%2DUgric%20substrate%20refers,was%20demonstrated%20by%20Ante%20Aikio.
I compiled a dictionary of the words of the substrate language. Is it accurate? I’m not sure, I tried a bit but in the end guessing was involved, even though I studied some of the sound changes from Pre-Saamic (Proto-Uralic) to Proto-Saami.
Some of the words were loaned individually into multiple Saami languages thus they can be traced back to multiple but similar sounding protoforms.
**aðoja > *vuoδōjē game, prey
**ajɲɕ-ojik~æk ~ij- > *ińc-ujëk~-āk outermost island (in names)
**ara > *-ērē mountain (in names)
**arŋi~e- > *jërŋë~vuorŋë open water in lake, middle of lake
**aronensi > *vuorunëssë predatory animal
**æjni > *ājnɤ thin, freshly fallen snow
**ætri > *jierttɤ large, round mountain
**čüŋkä > *cëŋkē stub, support, Fi. *tünkä
**ek > *jeakk- isolated mountain (in names)
**e(ta)sma ~eŋt- > *jie(tē)smē~(ðē) ~jievt/ð- young swan
**icxes~-ke > *ëčkës sheet ice
**ilɲi > *ëlńë gum (around teeth)
**ilpes > *ëlpës lynx, Fi. *ilbes
**jeɕi > *jësë~jëccë snow in summer
**jitko~jip- ~etka ~itkos > *itkō~ip- ~eatkē ~ëtkōs shady place
**kapli~ko > *kuoplë overhanging snowdrift
**kæwɕo > *kāvšō she-bear, she-wolf
**keðka > *keaðkē stone, rock
**ketka > *keatkē wolverine
**kolka > *koalkkee calm weather
**lewMo~ læŋkis~ lemkas > *lie(v)Mō~ lieŋkës -mkēs mild weather/ warm
**lijɕka~lajɕka > *liškē skin, surface, ? Fi. *liha
**makLi~me- > *muovLë~mëvLë deep snow
**merista > *mërëstē birch forest surrounded by bogs
**mori~mari > *muorë tree, wood
**ɲæli > *ńālë arctic fox
**norwa~narjo > *noarvē~*nuorjō seal
**okta > *oaktē rain shower
**pækta > *pāktē rock, steep mountain
**pecka~-xa > *peackē mountain pass, strait which dries in summer
**peŋke~pæ- > *pieŋkë wind
**perɕi~pærɕa > *përśë~ *pārśē isolated mountain, steep mountain edge
**poče- > *puocë-tēk be sick (with disease), Fi. *pote-dak
**puktas > *pokcēs~-tēs side channel of river
**ræpto > *raaptoo flat stone, stone slab
**ræsjo~-wɕi > *rāśśō~ rāvcë rain in cold weather
**rosni~ruxsni > *rusnɤ fog, mist
**sawki~so > *suovkkɤ dense thicket
**sæl~ saloj > *sāl- major island in sea (in names); ? **suolōj, Fi. *salo island
**sæpa-ɲi~-ka ~sæpilijŋki > *sāppānjë~ sāppēkkē~ sāppëliŋkë mouse
**sæpli-~e- > *sieplë- sink in soft snow
**šewšim > *sëvsëm hair, feather, Fi. *heühen
**skeɕ > *skiec(c) watershed (in names)
**skompæ > *(s)kumppā wolf
**slæpo > *(s)lāppō sinew thread
**suxɕa~sij/aj > *sucē~si- rime (ice when water in fog freeze to object surfaces)
**ɕaŋwi~ɕo- > *čuoŋvë light
**ɕapɕi > *čuopcë ice bridge
**ɕari-k~ŋ- > *cārëk/n/m uppermost lake (in names)
**ɕewras > *čeavrēs otter
**ɕexi~-ixa > *cëkē~-ë ~sëkē frozen snow (stuck to animalˈs foot), (stuck to skis)
**ɕopɕa > *coapcē foothold
**ɕutis~ɕestis > *cottës~cu- ~ cëstës snowdrift (hard, in summer)
**tajnta~tijnta > *tintē young salmon
**talo~tolmis ~talik > *tuol-ō~-mës ~tālëk frost on ground
**urti~-a > *ortë~ urtē treeline
**weɕɲi > *vëśńë brushwood, thicket