In searching for age-appropriate toys/activities for Ava, I recently stumbled upon the "Playtime Guide" on the Fisher-Price website. You can search by your child's age, and the site provides a list of suggested toys listed by type of play (of course, they are all Fisher-Price toys, but you could always find similar toys elsewhere). And perhaps even more helpful is the fact that the guide also provides play tips to "help your baby learn more" as they use the toys.
In addition to advice regarding age-appropriate toys, the site also provides a plethora of "play & learn activities," which are also searchable by age. For each activity, they list the materials needed, detailed instructions, and safety precautions.
This is a very helpful (and free) resource that I definitely plan on checking on a regular basis!