I can say about South East Asia/Philippines where I came from. Yeah 0w20 or 0w16 is mostly unheard of obviously. 5w30 5w40 10w30 10w40 15w40 20w50 are the common grades usually. DIY oil change is not that popular because of the hassle of oil disposal, (yeah we I know the importance disposing used oil properly). Another reason is most gasoline station has oil change bay that you can just pull in and ask for an oil change. You can talk to the the mechanics while they are doing your oil change and you can even walk under your car while it's up on the lifter. So you can see that they are doing it right. Most common oil brands are
Shell Helix, Caltex (Chevron), Petron. Mobil1, Valvoline, Castrol, Idemitsu, Zic. OEM oils like Toyota, Honda are mostly made by one supplier which is Caltex(Chevron). Motul and Amsoil have presence and are popular with the enthusiasts crowd. I bet even the cheapest oils here are not poor quality because Philippines especially the Metro Manila area has one of the most demanding driving conditions in the world and when you go to the auto shops most of their work are suspension related or emissions related. (engine throwing codes or carb engines that out of tune). You can see one or two engines that needs to be rebuilt but not because of oil related failure but mostly neglected engine or the most common, failed cooling system due to age or lack of cooling system service that led to overheating.