It seems like the flat pedals I see most frequently are either Race Face Chester, or various Shimano like the Saint. The Chester’s come in a wide range of colors. The Shimanos look serious and the current XT comes in two platform sizes.

I like a fully molded or rubber treaded pedal better than pins even though they are not as grippy. I’ve regrown enough shin skin.

I sometimes use SPD’s. I most recently installed those on my trike because it needed foot retention for safety and the big Power Straps it came with were unlikable.