Non Uber Legendaries Pokemon. Some legendaries aren't even tier 2[standard or ou] due to various reasons such as movepool and type. Machamp counter, karate chop (legacy) dynamic punch.
Tournament legal means that the legendaries aren't in ubers. Top 10 strongest mythical pokémon, ranked when looking at the box art legendaries. The legendaries that are too good for ou are placed in ubers, so no legendaries in ou are op just because they are legendary.