Chaosmancer
Legend
*from the playtest
35' walking speed and get big is the base.
Subspecies gives you another thing proficiency times a day, based on a giant
Cloud teleports
Fire adds fire damage.
Hill knocks prone
Storm is reaction damage.
Keep in mind, species are a bit weaker than before, as background got a half-feat.
Two things you missed.
Stone giant still gets the d12 reduction
Powerful Build includes advantage to break free of grapples.
The increase to large size also increases their movement speed by 10 ft, giving them a temp 45 ft and advantage on strength checks (but not saves)