SQL Server Trace Flags
Maintaining an up-to-date list of SQL Server Trace Flags is time consuming, and difficult since the majority are undocumented.
Aaron over at SQLCrossJoin.wordpress.com maintains an incredibly detailed and comprehensive list of trace flags at https://sqlcrossjoin.wordpress.com/category/trace-flags/.
As of early 2019, the most current version of the SQLCrossJoin trace flag document is version 6.