I mostly ride clipless, but when I'm running errands on the road bicycle, with a lot of walking involved, I use a pair of duatlon/triathlon adapters. They have a 6" long by 3"wide platform and double tongued plastic clips that accept 1" wide straps. On the ATBs I have SPDs.

Sometimes, I used to make my own toe clips by bending coat hanger wire. After all, the main purpose of the clip is to hold the strap open and in position . The shoe shouldn't be touching the clip, except in the vicinity of the strap loop. A little padding this area prevented the wire from aggravating the foot.