Command and Conquer - GDI Juggernaut

By 2047, the only walker still in GDI service is the Mk. III Juggernaut mobile artillery system – a direct descendant of the Mk. I Juggernaut in TW2. The Mk III is based on a Mk. II Titan chassis with a new turret and crew pod, upgraded cannons, and a next generation fire control system. Because these vehicles are intended for indirect fire support and are not expected to be on the front lines, the advantages conferred by all-terrain navigation were deemed worthy of the risks.

Source: http://cnc.wikia.com/wiki/Juggernaut_(Tiberium_Wars)

Also check out the GDI Mammoth tank:
https://www.thingiverse.com/thing:2410383

And GDI Firehawk:
https://www.thingiverse.com/thing:2431192

TODO: Will add some more info later