I would like to make a special mention of the Skoolzy line of products. I used several of their toys for my son, and they were among his favorites. His therapist loved them as well, using them frequently in therapy. They were designed by a mother to help her child’s early development.
The Skoolzy nuts and bolts toy was another favorite. He could play with them daily and not get bored. They also incorporated shape and color matching as an added bonus.
Pegs Peg Art Lacing Beads Nuts & Bolts

For parents looking for a cheaper or free version, many of these games can be found second hand. Pinterest is also full of examples of how to craft your own. One of my favorite examples is activity boards. You can make them yourself for relatively little money, and they are full of fine motor skills fun.