The Ennead branch most readers want
Start with Geb (earth) and Nut (sky). Their children Osiris, Isis, Set, and Nephthys form the core sibling set in Heliopolis. Osiris rules, Set kills him, Isis restores him temporarily, Horus is conceived, and the succession fight becomes Horus versus Set rather than a simple father-to-son handoff.
MythCairn's wider Egyptian gods overview compares this Heliopolitan scheme with Memphis and Hermopolis, which do not use the same opening cast.
Where Anubis and Nephthys complicate the chart
Middle and New Kingdom sources sometimes call Anubis the son of Osiris and Isis; other texts make him Nephthys's son, with Osiris or Set given as father depending on the version. Diagrams that draw one solid line for Anubis flatten a disagreement Egyptian priests kept parallel for centuries.
The Eye of Ra and Eye of Horus motifs orbit this same court but belong to different myth cycles; do not merge them into one generic "eye symbol" on the tree.
How this tree connects to Osiris's symbols
The djed pillar myth, Isis retrieving Osiris from the pillar at Byblos, is a story told to explain a symbol that already belonged to Memphite gods. Horus's eye, damaged in the contendings with Set, becomes a fractional measure in medical and economic texts.
For symbol-by-symbol evidence rather than genealogy alone, use Osiris's symbols and this page together.