My own exposure to Estrada's work was on the Legion of Super-Heroes title among other places. Estrada was the artist on the first 11 issues (out of 15) of the Karate Kid title, in addition to drawing several Legion comics - Superboy and the Legion #232 (the Klordny/Immune story), #234 (the Bounty and the Composite Legionnaire story), and Legion v2 #261 (the Space Circus of Death story). I believe he also worked on the Amethyst: Princess of Gemworld series as well way back when, but could be mistaken on this.
Another man with a part in the legacy of the Legion of Super-Heroes comics.
Rest in Peace, Ric Estrada (1928-2009).