The Speed Force shows Barry his mother's grave, and later he visits it with Iris in episode 2x21 "The Runaway Dinosaur". The team attends Barry's father's funeral in episode 2x23 "The Race of His Life". Barry finds Joe visiting Iris's grave in the future in episode 3x19 "The Once and Future Flash". Appears in 1 more episode.
Daniel attends his old mentor's funeral and meets some old colleagues in episode 4x13 "The Curse".
Flynn visits the graves of his wife and daughter in episode 1x06 "The Watergate Tape".