You won't find any true mech games with melee combat because it simply doesn't make any sense whatsoever. The only games that will have this will be more arcade-style "mecha" games that have robots able to move and act much like oversized, metal humans. Typically the robots in such games have very humanoid designs to make this seem at least somewhat plausible, rather than being tanks with legs (sometimes literally) as in MechWarrior and the like, which are more suited to manoeuvring at a distance and exchanging fire (much like their present-day predecessors).
There are some very good reasons for why melee combat became forcibly extinct on the battlefield, and this will not change in the future no matter how advanced technology gets; human combatants are at a severe, constant disadvantage when attempting to close to melee range against foes with ranged weapons, a situation which has only become worse as the overall range and accuracy of ranged weapons has increased over the centuries, and this situation would be further exacerbated when trying to achieve the same with mechs or other vehicles against similar targets armed with traditional long-range weapons for the very purpose of crippling or obliterating foes from afar before they are able to close to their own firing range (let alone as close as melee range). Even then that's not taking into account just how huge mechs and other vehicles are compared to people; even if the enemy had only quite short-range weapons there would be a very generous amount of time between moving into the enemy's targeting range and actually reaching melee range with them during which the enemy would have ample time to unload a volley or two and have a vastly higher chance of hitting simply because the target is so enormous, and the lighter armor necessary for moving at ideal speeds for melee combat would mean they would go down even faster than a regular mech once they get within range. Additionally, since melee mechs would have to be fast-moving to stand a chance they would surely be putting out a larger heat signature, which would make heat-seeking weapons more accurate and able to reliably pick up a heat signature from a greater distance.