Ghaele (celestial, 25), Planetar (celestial, 30), Solar (celestial, 35), Succubus (demon, 20), Bebilith (demon, 30), Vrock (demon, 20), Hezrou (demon, 20), Glabrexu (demon, 20), Nalfeshnee (demon, 20), Marilith (demon, 20), Balor (demon, 30), Kyton (devil, 20), Hellcat (devil, 20), Cornugon (devil, 20), Gelugon (devil, 20), Pit fiend (devil, 25), Wyrm dragons (20), Clay golem (20), Stone golem (30), Iron golem (50), Night hag (20), Nightshades (25), Rakshasa (20), Noble salamander (20), Death slaad (20), and Tarrasque (25) - and those are just the ones from the MM. Having just looked through the list, it seems 15-20 are the most common DR values, as opposed to 5-10 in 3.5. There are almost no monsters with DR 5 or 10.