I have Shimano A530 dual sided pedals on a beater bike. The clipless side is SPD and the other side a platform. The platform side is not super big but works fine. Shimano M324 are similar but with a different and larger platform size. The main penalty with these pedals might be weight(?) and cost. Shimano entry level road clipless R540 SPD-SL style pedals can often be found for less.

Shimano SPD-SL road pedals tend to be sturdy enough that you can ride them with sneakers tho it's a smaller contact area with street shoes/sneakers. I know some people ride on Speedplay pedals with regular shoes too, but they seem really small and slippery to me.