Minecraft wiki entry for Oak, associated text: Apple (chance of dropping when breaking leaves)
Bee Nest (if spawned on an oak near flowers)
Mushrooms‌[Bedrock Edition only] (if present on a fallen oak log)
Oak Leaves (harvested with shears)
Oak Log (harvested with any tool including hands)
Oak Planks (created from a log in the inventory crafting grid)
Oak Sapling (chance of dropping when breaking leaves)
Stripped Oak Log (created by using an axe on a log)
Vines (harvested with shears from a swamp oak, or from a dying tree‌[Bedrock Edition only])
Stick (chance of dropping when breaking leaves)