Assalamwalekum my dear brothers & sisters. Yes, it is possible to earn reward even after your death. Do remember every single smallest good deed also counts and we never know for which good deed Allah may send us to Jannah..
Please try to perform these following good deeds to get rewards even after you die.
1) Participate in building a Masjid. Muslims Pray, You earn. : Whether you donate money or do labor work, if you are helping to build a Masjid then you will earn reward as long Muslims are praying in that Masjid.
2) Donate a wheelchair to a hospital. Patients use, you earn.
3) Give a copy of Qur’an to someone. People read, you earn.
4) Place water cooler in a public place. People drink, you earn.
5) Plant a tree. People & animals use for food or shade, you earn.
6) Teach or Tell Some one good thing ( Verse of Quran, Hadith, Dua etc )