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...

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