>>424284/m/ tolerates newfags if they're polite. That said, generally 90s and 00s gundams, any Mazinger or Getter Robo entry, and anything recent that isn't Valvrave or Active Raid would be good starting points for beginners that have only dipped their toes. If you have trouble with picking a specific, look at Super Robot Wars cast lists, look up some all attacks videos on youtube, and check out your favorites as long as they are not originals.
If you want some specifics and you don't mind sex shit:
-Gundam SEED and Destiny
-Gundam Wing
-G Gundam
-Gundam X
-Gundam 00
-Shin Mazinger Z
-Getter Robo Armageddon
-New Getter Robo
-Zegapain
-Gravion
-Aquarion trilogy
-Fafner (first series isn't much, but the movie and sequel are worth it)
-Gun x Sword
-Godannar
-Comet Lucifer
-Dancouga
-SPT Layzner
-Xabungle
-Aura Battler Dunbine
-Ideon
-Gaiking (both the 70s and remake versions)
-Nobunaga The Fool
-Aldnoah Zero
-Samurai Flamenco (not technically mecha, but it's a love letter to toku)
-Appleseed Alpha
-Big O
-Neo Ranga
-Dai-Guard
-Demonbane
-Steel God Jeeg
-Great Dangaioh
-VOTOMS (watch the original series and Merowlink first, everything after can be viewed whenever although Finder is so stand alone you could see it right after reading this post and not be spoiled)
