Mine is pic related, the Victory Gundam. What I like about it is how modular the mobile suit is. It's the result of years of ms tech late into the Universal Century where now the Gundam is mass produced. In the show the rebel forces are shown to have a stockpile of Gundams in a bunker so they can burn through parts.
Honorable mention to the RX-79 G ground type Gundam from 8th MS Team.
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Confession time: I never knew why the "happy music" (Soldiers of Sorrow) would play during the Jaburo mission. It wasn't until I got back into anime a handful of years ago and watched the movie trilogy until it clicked lol.
I was too stupid to understand it as a kid, but Zeonic Front still holds up as a pretty cool tactics shooter.