Achievement description is: win a round on 8 different arenas
There's 14 different arenas split between 3vs3 and 2vs2/1vs1 modes.
For 2vs2/1vs1 modes, the following maps are available:
Ring Ruckus, Cliff Clash, Bastion Bash, Brawlin' Bog, Pinnacle Punch-Out, Swinging Spire, Roller Rumble.
For 3vs3 modes, the following maps are available: Astrolabe Escapade (only in Knockout and Oddball modes), Rockslide Ridge, Crumbling Keep, Sinking Swamp, Spellbound Study, Gutsy Gauntlet and Spinning Spikes.