I don't know of any major carrier which offers freebies along the line of UDU's, other than US carriers on domestic routes. As a general matter, pretty much all carriers dole out OPUPS, but those are for the operational convenience of the carrier, not a perk for a passenger.
Back in the very old days before audits picked this stuff up and when GS meant something, agents might occasionally sneak a passenger they knew into F. But, that went out with more sophisticated software and the end of GS as a secret program.
The reality is that the US domestic programs allowing upgrades without cost, e.g. paid, miles, some form of special certificate, are fairly unique to the US and came about largely during the financial crisis. UA, by way of example, awarded and sold what amounted to upgrade certificates based on miles and then shifted into the UDU mode when the bottom fell out of the market.