What were the good works of those crucified with Jesus?
Well, the so-called "good thief" bore bold witness and gave one of the most powerful and eloquent testimonies in the entire history of Christianity, and the words from his brief "mini-sermon" painfully given from his cross have been passed on to billions and billions of Christians and other people through all these centuries since he died. Most preachers and other Christians will never reach even a small fraction of that many people with their own personal witness and testimony in this life.
He also elicited an amazing response from our Lord from His own cross, which made it clear to everyone (including Unitarians and Jehovah's Witnesses of today - and everyone else) that He (Jesus) indeed did have the Divine Power and Divine Authority to offer a dying person eternal salvation.
The brief words of that "good thief" (see Luke 23:42) also inspired a very famous prayerful hymn/chant of today:
Jesus Remember Me When You Come Into Your Kingdom
(You could say he composed the lyrics for that song.)