Wonder no more, as here are a few of the more important Batman/Supergirl meetings of the Silver and Bronze Age!
Brave and the Boldwith a different co-star, in B&B #63 in 1965), but it took until Brave and the Bold #147 (February, 1979) for Batman and Supergirl to team up in B&B, with "Death-Scream From The Sky!" in a story by Cary Burkett and beautiful art by Jim Aparo, with the pair facing off against JLA foe, Dr. Light and his Children of Light.
This story proved popular enough to have the duo reteam in Brave and the Bold #160 (March, 1980) by the same creative team, with Batman and Supergirl working to save Supergirl's adopted father, Fred Danvers, from Batman foe, Colonel Sulphur, in "The Brimstone Connection".
World's Finest Comics
Superman and Action Comics
...just letting you know so you won't have as hectic a day as Supergirl did, trying to find these stories!