This list is IMHO (based on my personal experience and information from other DXer's blogs in Internet). It is probably incomplete, so any additions and corrections are greatly welcome. Please note, that there are only international stations in this list (mentioned in the "International Radio" section of WRTH), because some local stations (e.g. Rádio Nacional da Amazônia or Radio Nikkei) are still sending paper QSLs too, but they are absent there.
And yes, Bible Voice seems to be also a regular "paper QSLer". Thanks. I included this station into my list. The same for Radio Exterior de España (didn't know the current QSL-status for them).
As for China Radio Int'l, Voice of Indonesia, Radio Romania Int'l and Radio Vatican: some language sections (not all) are still sending paper QSLs.
PBS Xizang / Holy Tibet / China Tibet Broadcasting: I have sent reception reports several times to them (by snail mail too) and even received some promises of QSL once, but still never got any paper confirmation from this station. No any reply from the Voice of Tibet. Never received any QSLs from Radio Kuwait after many years of sending reception reports either, only nice table-top calendars yearly. So, the result is strictly depends on a personal luck too.