The Lithuanian Swadesh list includes the following words and I was able to find numerous relatives to Gaelic. I could be wrong about some. Obvious similarities to Latin in some cases too, maybe loanwords. But one can see the Indo-European connections.
Lithuanian and Celtic had no direct contact with each other AFAIK, although Celtic was in contact with Vasconic, Romance, Germanic and Slavic... And Lithuanian was in contact with Slavic and Germanic, maybe Finno-Ugric...
Baltic and the older layers of Celtic languages are known to be pretty conservative, if not archaic, within the context of IE languages. If you look at Old Irish the ressemblance will be blatant.
Lithuanian and Celtic had no direct contact with each other AFAIK, although Celtic was in contact with Vasconic, Romance, Germanic and Slavic... And Lithuanian was in contact with Slavic and Germanic, maybe Finno-Ugric...
Obviously numbers...
Sniegas - Sneachd — Snow
In — An(n) — In
Najas — Nuadh — New
Marios — Muir (genitive mara) — Sea
Srūti (to flow) — Sruth (stream)
Mirti (to die) — Murt/mort (murder)
klausytis (to hear) – cluas (ear), cluinntinn (listen)
sekla — sìol — seed
Senas — Sean — Old
Vyras - Fear (plural Fir)- Man (wer(e))
Dantas (tooth) - Deudag (toothache)
Ugnis (fire) — Aigeann (fireplace)
Raudonas — Ruadh — Red
Dienas (day) — Di- (day in day names) – Day
Pilnas — Làn — Full
Kaire — Ceàrr — Left
Dešinė — Deas — Right