HABA makes great wooden toys. www.rosiehippo.com
is a great site for natural toys, as is www.threesisterstoys.com
Everybody feels differently about plastic--my feeling is, if you already have them, you may as well keep them--the damage has been done, kwim, as far as using those resources. The toy is there, you have it. Throwing it away prematurely just puts them in a landfill all that sooner.