There are a huge variety of products for repairing holes and rot in wood. Editor Brian Pontolilo describes the differences between wood fillers, putties, epoxies, and spackle, as well as when each is most appropriately used.
The Best Wood Fillers for Your Home
Deciding on Wood Fillers - Fine Homebuilding
Deciding on Wood Fillers - Fine Homebuilding
How to Use Wood Filler to Repair Furniture - The Lavender Homefront
I didn't match my wood filler color with the oak very well. What are my options? : r/woodworking
Filling Nail Holes in Stained Trim - Fine Homebuilding
How to Stain Pine
Foyer stairs: sanding and making wood filler
Box-Joint Basics