You can't have dirt without diggers! One of our most go-to activities!
Simple activity: Find a dirt/rock/sand pile, throw a digger, dump truck, shovel, etc and throw your toddler in the pile with clothes you don't mind getting dirty! We keep our "digger pants" that stay dirty in a bag for him to use each time. Otherwise, get dirty little one, explore your world, textures, create, play, imagine and practice your fine motor skills too!