While Toxic Spikes aren't as useful as they once were, I think it would be an exaggeration to say they are useless or bad. While they aren't very helpful vs some teams, they can be game breaking vs others. Albeit this list is growing smaller and smaller as time goes on, but Toxic Spikes do have use and can really help in wearing down your opponent.
Also for hazards layer's, I would definitely add Skarmory to the list as it is a fantastic layer of Spikes. I think other offensive layer's like Terrakion/Garchomp/Aerodactyl should also get a special mention as they are reliable Stealth Rock layers and have been used many times to a lot of success. For the spinners section Starmie, Forretress, and Tentacruel should also get mention. In addition to Donphan, these are the most popular spinners in the metagame (and really the only ones used). And since Spinners are being included, maybe Spin Blockers can also get a mention. Gengar, Jellicent, and Sableye are the primary Spin Blockers in BW but Pokemon like Chandelure and Golurk can fit niche needs.