ただろ

was, were (…ing), …ed (right?)

→ だ
た Past tense + だろ Conjectural / seeking confirmation
auxiliary · informal, past tense Rare #40,528
was, were (…ing), …ed (right?) A casual contraction of ていただろ, used to seek confirmation.
JA: 昨日ここで待ってただろ。
EN: You were waiting here yesterday, right?
Conjugation of だ

泣いてただろ

You were crying, weren't you?

— 映画 聲の形 (2016)

私はしっかりと世話を見てただろ?

I took good care of you, didn't I?

— ソング・オブ・ザ・シー 海のうた (2014)

運転手をしてただろ?

You were a driver, right?

— 暗殺の森 (1971)

拳銃を持ってただろ?

You had a handgun, didn't you?

— 暗殺の森 (1971)