Atlantis has what is probably the best collection of masks of any wrestler. He doesn't have nearly as many as El Hijo del Santo, but in the comparatively few mask matches he had Atlantis took the masks of Kung Fu, Mano Negra, Villano III, and Ultimo Guerrero. I'm not sure if Hijo del Santo has one mask that was as historically important as any of those four (well, I guess Kato Kung Lee's), and Atlantis still has some nice second-level ones like Talisman's. Santo the original might be ahead but I don't know enough to tell just from looking at the list of his wins.
The 1993 anniversary show headlined by Atlantis vs Mano Negra was one of the rare CMLL bright spots during a down period for the company, and it came at a time when their status as the number one promotion in Mexico City was actually being threatened. Vampiro was considered a bigger draw at the time, but it was Atlantis who saved the day. Apparently in the immediate aftermath the promotion went right back to drawing poorly with only rematches of the anniversary main event drawing anything for them.
Having (arguably) great matches in 1984 and in 2015 is an impressive feat, even if he was carried for the Satanico match in '84. I don't think he had a whole lot of MOTYCs during his prime as a worker, but I really do like the Blue Panther match from 1991 and the Emilio Charles match from 1992. He seemed to drop off in a major way after 1992. It's either a backhanded compliment or a forehanded insult, but that played a major part in the decline in CMLL match quality from 1992 to 1993, IMO. So many 1993 matches when you see Atlantis' name and go in thinking they might be awesome, and then they aren't, in part because he isn't. Goes to show how important having him in there at the top of his game was in the years before that.