>>1123087This chart has a lot (not all) of the 10/10 stuff. For beginners there's a variety of things assuming age and episode count are not big factors. /tg/'s wiki has a wide selection on their page about /m/ (which ironically the janitor on /m/ won't allow posted):
https://1d4chan.org/wiki//m/Personally there are several titles to go with:
-70s super robot cheese: Combattler V, Mazinger Z, Grendizer, Getter Robo, Steel Jeeg, Daikengo, Gaiking, Astro Ganger, and Zaombot 3.
-70s general mecha cheese: 30,000 Miles Under The Sea, Hellhound Liner 0011, the original Casshern, and Hurricane Polymar.
-80s super robot productions: God Mars, Acrobunch, Goshogun, Braiger, the original Dancouga, Daiohja, Shin Tetsujin 28 (same continuity as God Mars), Ideon, Baldios, and Govarian.
-80s real robot cheese: Dougram, VOTOMS, Dorvack, Xabungle, L-Gaim, Dragonar, the original Bubblegum Crisis, and Crusher Joe. Yeah, Gundam entries don't get amazing until the 90s.
-90s cheese general: Getter Robo Armageddon, Raijin-Oh, Jushin Liger, Ryu Knight, Granzort, Evangelion, any Braves series that isn't Goldran (it is a pathetic comedy and takes too long to get good), Dangaizer 3, Big O, Neo Ranga, Argento Soma, Dai-Guard, Detonator Orgun, and NG Knight Lamune.
-2000s wonders: Gundam Seed and Destiny, Gundam 00, RahXephon, Gun X Sword, Godannar, Gravion, Full Metal Panic, Code Geass, New Getter Robo, Shin Mazinger Z, Burst Angel, Genesis of Aquarion, Starship Operators, Dancouga Nova (it's a remake), Steel God Jeeg, Legend of Daiku Maryu Gaiking (remake), TTGL, and Fafner.
-2010s surprises: Nobunaga The Fool, Unit Pandora, Comet Lucifer, Majestic Prince, Gargantia, Buddy Complex, Price of Smiles, Star Driver, Samurai Flamenco, Mazinkaiser SKL, RobiHachi (more of a comedy), M3 The Dark Metal, Unicorn and Narrative Gundam, Gundam Build Divers, Heavy Object, Eureka Seven: Astral Ocean, and Lagrange.
There's a lot more, but these are safe entry points.