Lewis & Short

ŏpĭfer, ĕra, ĕrum, adj. [ops-fero], aidbringing, helping (poet. and in post-Aug. prose): deus, Ov. M. 15, 653: FORTVNA, Inscr. Orell. 1753.
Of things: folia, Plin. 16, 13, 24, § 64: fidem opiferam sociūm advocant, Enn. ap. Non. 144, 14 (p. 109, v. 165 Vahl.).