Change table, foam interlocking mats if you don't have carpeting, keep all your cords hidden or taped down to the wall, door knob handles, gates top of stairs, bottom of stairs and get a pressure mounted on to keep them confined in one room if necessary. For toys, mine love my tool bench, book shelf, little peoples car garage, ball pit, ride on toys, balls, bubbles, outdoor climbers, slide sandbox.
I ask parents to bring their own playpens and I send it home on the weekends if they need it.