Good works that you do in this life, may have hidden flow on effects, which you might not see until after your death e.g. if you give a prayer card with the St. Gertrude prayer for the relief of the Holy Souls in Purgatory to someone, they might say it many times, but might also teach it to someone else. That person might put it on a blog or a website or make cards with the prayer on it to distribute. People who come to that website or receive one of the cards, might recommend it to their families, who then might spread it elsewhere. From there the good works might continue to spread.
You may have tried to promote a good work and no one appeared to be interested, but there are sometimes factors which you do not see, and the work might also have a good works flow on effect.
Prayer of St. Gertrude the Great.
Eternal Father, I offer Thee the most Precious Blood of Thy Divine Son, Jesus, in union with the Masses said throughout the world today, for all the holy souls in Purgatory, for sinners everywhere, for sinners in the universal Church, those in my own home and within my family. Amen.
The web page has accounts of the intercession of The Holy Souls in Purgatory, for their benefactors in cases of illness, addictions, cars that won’t start, infertility problems, protection in accidents, conversion, chronic insomnia, their help for people who are experiencing major trouble with city councils, success with projects, employment, real estate, television sets that don’t work properly, finding lost property and trouble with relations, etc. and prayers and ideas on how to help The Holy Souls in Purgatory.