Looking at https://github.com/softdevteam/grmtools and it's documetnation at https://softdevteam.github.io/grmtools/master/book/errorrecovery.html it mentions the CPCT+ error recovering algorithm from Don't Panic! Better, Fewer, Syntax Errors for LR Parsers here Don't Panic! Better, Fewer, Syntax Errors for LR Parsers .
It seems an interesting proposal and parsertl so far doesn't have any error recovery mechanism, would be nice to have something like CPCT+.